Minimum set of apk in /system for S2 boot and a minimum launcher

So, basically, I have root access on my S2. The phone is GT-I9100, with Android 4.1.2 Build Version: JZO54K.I9100XWLSD

I can remount the system partition rw, what I want to know is:

If I do a backup of ALL apk (or just a dd of the entire partition), I wanna remove as much apk (applicaitons) possible without compromizing system boot, and maybe a launcher such that I can at least relaunch a terminal and if something is not working properly, incrementally add apk, until the system seems stable.

What would be best, is a guide like Linux From Scratch, something like Android From Scratch, that explain the practice of building a rom, from source, customize it for the S2 or other devices, and more important, explain the USER Level part of Android. i.e. boot, init, and apk needed in all different steps..until a properly gui is up and running (a launcher).

Thanks for any info.