interesting :)

[kronikpillow]

Interesting ... I'v been working on something similar, and have achieved same result ... athou i haven't taken a detailed look at your installer yet, i'm wondering ... is there any valid reason to not exclude entire /var from snapshots except the pacman database? which is on my setup mitigated by moving DBPath to /usr/lib/pacman from /var/lib/pacman ... in my current running setup, everything seems to work so far without any issues ...

Grub-btrfs with the grub-btrfs-overlay-fs flag allows you to boot with a read-only snapshot, totally eliminating the breaking up of /var ... unless, there is something else im not aware off?

https://github.com/kronikpillow/arch-install ...

also, another difference seems to be that yours is self-automated ,mine has manual steps as i haven't learned yet that kind of shell scripting :)