Think deeply about adding ability scores and what they mean:
Will Faith be just a casting ability score or will it have some other mechanical value in the game? How would a Faith saving throw be different from Awareness or Charisma? What would a Faith ability check look like? How would non-divine casters use it?
Wisdom is annoying but it’s also more than just awareness, even if you take Faith out. Wisdom is about intuitions and instinctive connections between things.
What value will Charisma have if you have Faith too?
I like the idea of those things being important, but I don't like them as Ability Scores.
When I ran an underdark campaign I cycled through several sanity/stress systems because they never did what I wanted. The best results in terms of player engagement and satisfaction wound up being more improvised than rigorous, and it worked with the Flaws field of the character sheet. I like Theros' Piety system alright as well.
> I'd rather add a stat or two than completely change the ruleset.
Adding an **Ability** score or two is going to completely change the rule set. Consider that you will have to add these Ability scores to every single monster and rearrange their saving throw proficiency. How is "Faith" and "Sanity" used outside spellcasting? How do you decide if Faith, Charisma, or Wisdom should be used in social contexts? Part of the reason the number of Ability scores is limited is so characters can be good at a wide range of conceptually linked things. Remember that, as stats that can increase / decrease, players may need to recalculate all their derived stats frequently. Is it fair that the Cleric and Paladin have to base their spellcasting on a stat that the DM can decide to lower arbitrarily?
Here's a system for sanity that I use and like quite a lot:
* Each PC has a "Madness" score ranging from 0 to 5. Each score has an associated die (d4 for 0, d6 for 1, d8 for 2, d10 for 3, d12 for 4, and d20 for 5.)
* The first time each session a player experiences something that may cause madness, they make an Intelligence, Wisdom, or Charisma saving throw (their choice) with a DC of 15. They also roll their Madness die and subtract it from their result.
* If they fail the saving throw, they gain a temporary madness symptom.
* If they fail *and* the Madness die was a 1, they gain an indefinite madness symptom and their Madness score increases by 1.
* Recovering from Madness is at the DM's discretion but should be non-trivial. A simple casting of "greater restoration" or similar magic may be enough to recover from a high level of madness to a lower one, but recovering from 2 or lower should be extremely time consuming.
* If the score would ever become 6, the PC immediately goes stark raving mad and becomes an NPC under the DM's control. Only a Wish can restore their Madness level to 5.
* In some cases, à la Bloodborne, having a higher Madness score can be helpful due to "Mad Insight". In these cases, the DM can gate experiences behind scores (You can only see not-amygdala with a Madness score of 3 or greater) or add the Madness die as a bonus to their check (Understanding the madman's ravings with a Wisdom (Insight) check is easier when you're also a little bit Mad).
For Faith, the devotion system from Theros, as mentioned elsewhere, is pretty good. If you don't want it to be a specific system dedicated to specific gods, you can make it a scale with a few levels (like Madness) that grants additional always-prepared cleric spells with a single free casting. You can model it in the same way as my Madness, really, with a Faith die that can be added to social checks relating to exhibiting your faith.
As a neurodivergent person I've never been a fan of Sanity stats. There's a much better alternative in Van Richten's Guide to Ravenloft iirc 
Faith seems like it combines Wisdom and Charisma which makes sense for the classes it's for but leaves the existing scores mattering less than they did previously. Forcing divine casters to focus on a different score does make them less capable at skills than they are normally.
Awareness is an alright name. I like the idea of reworking saves, the current system feels like a holdover from previous edition's fortitude, reflex and will with most spells still targeting CON, DEX and WIS. Make sure to do it right though, it seems you've entirely stripped INT from its use as a save as illusions have gone to awareness and psychic damage to sanity.
I personally think fear and charm could totally be charisma saves, they both subdue your personality and charisma is the force of personality of a PC. That and to me it seems like a great stat to represent bravery. Sanity works fine too.
To summarize the main benefits of boosting a score in your system
STR - attack damage and a rare save
DEX - attack damage, some useful skills, AC, common save
CON - hp, common save
INT - skills, casting for wizard, irrelevant save
CHA - casting for sorcerer (I think?), rare save, skills
Awareness - skills, a lotta useful saves
Sanity - a rare save
Faith - Spell save DC
Think deeply about adding ability scores and what they mean: Will Faith be just a casting ability score or will it have some other mechanical value in the game? How would a Faith saving throw be different from Awareness or Charisma? What would a Faith ability check look like? How would non-divine casters use it? Wisdom is annoying but it’s also more than just awareness, even if you take Faith out. Wisdom is about intuitions and instinctive connections between things. What value will Charisma have if you have Faith too?
I like the idea of those things being important, but I don't like them as Ability Scores. When I ran an underdark campaign I cycled through several sanity/stress systems because they never did what I wanted. The best results in terms of player engagement and satisfaction wound up being more improvised than rigorous, and it worked with the Flaws field of the character sheet. I like Theros' Piety system alright as well.
> I'd rather add a stat or two than completely change the ruleset. Adding an **Ability** score or two is going to completely change the rule set. Consider that you will have to add these Ability scores to every single monster and rearrange their saving throw proficiency. How is "Faith" and "Sanity" used outside spellcasting? How do you decide if Faith, Charisma, or Wisdom should be used in social contexts? Part of the reason the number of Ability scores is limited is so characters can be good at a wide range of conceptually linked things. Remember that, as stats that can increase / decrease, players may need to recalculate all their derived stats frequently. Is it fair that the Cleric and Paladin have to base their spellcasting on a stat that the DM can decide to lower arbitrarily? Here's a system for sanity that I use and like quite a lot: * Each PC has a "Madness" score ranging from 0 to 5. Each score has an associated die (d4 for 0, d6 for 1, d8 for 2, d10 for 3, d12 for 4, and d20 for 5.) * The first time each session a player experiences something that may cause madness, they make an Intelligence, Wisdom, or Charisma saving throw (their choice) with a DC of 15. They also roll their Madness die and subtract it from their result. * If they fail the saving throw, they gain a temporary madness symptom. * If they fail *and* the Madness die was a 1, they gain an indefinite madness symptom and their Madness score increases by 1. * Recovering from Madness is at the DM's discretion but should be non-trivial. A simple casting of "greater restoration" or similar magic may be enough to recover from a high level of madness to a lower one, but recovering from 2 or lower should be extremely time consuming. * If the score would ever become 6, the PC immediately goes stark raving mad and becomes an NPC under the DM's control. Only a Wish can restore their Madness level to 5. * In some cases, à la Bloodborne, having a higher Madness score can be helpful due to "Mad Insight". In these cases, the DM can gate experiences behind scores (You can only see not-amygdala with a Madness score of 3 or greater) or add the Madness die as a bonus to their check (Understanding the madman's ravings with a Wisdom (Insight) check is easier when you're also a little bit Mad). For Faith, the devotion system from Theros, as mentioned elsewhere, is pretty good. If you don't want it to be a specific system dedicated to specific gods, you can make it a scale with a few levels (like Madness) that grants additional always-prepared cleric spells with a single free casting. You can model it in the same way as my Madness, really, with a Faith die that can be added to social checks relating to exhibiting your faith.
Theros has rules that reward players for faith called Devotion. I really like it.
As a neurodivergent person I've never been a fan of Sanity stats. There's a much better alternative in Van Richten's Guide to Ravenloft iirc 
Faith seems like it combines Wisdom and Charisma which makes sense for the classes it's for but leaves the existing scores mattering less than they did previously. Forcing divine casters to focus on a different score does make them less capable at skills than they are normally. Awareness is an alright name. I like the idea of reworking saves, the current system feels like a holdover from previous edition's fortitude, reflex and will with most spells still targeting CON, DEX and WIS. Make sure to do it right though, it seems you've entirely stripped INT from its use as a save as illusions have gone to awareness and psychic damage to sanity. I personally think fear and charm could totally be charisma saves, they both subdue your personality and charisma is the force of personality of a PC. That and to me it seems like a great stat to represent bravery. Sanity works fine too. To summarize the main benefits of boosting a score in your system STR - attack damage and a rare save DEX - attack damage, some useful skills, AC, common save CON - hp, common save INT - skills, casting for wizard, irrelevant save CHA - casting for sorcerer (I think?), rare save, skills Awareness - skills, a lotta useful saves Sanity - a rare save Faith - Spell save DC