I updated the OP, use the free CCleaner app to find out each and every service using your RAM, and use TitaniumBackup to freeze them. Freezing seems to bypass the bootloop issues that arise when deleting system apps, plus if you ever need them you can just re-enable them, eg freeze Google Services to save a ton of RAM and unfreeze them whenever you need to update your apps.

That being said I can't see the benefit of uploading a modded version of a proprietary rom, I still get occasions where stock apps hang up or force quit. Removing random parts of a system you didn't build yourself will reduce system resources yeah but on the same token, bugs everywhere.

Better to just backup your own phone and freeze what sysapps you personally don't care for, for example I got rid of the native video and gallery apps, but still keep the alarm clock/music apps. Also, apps you download personally can hog just as much ram as sysapps, so you'll have to deal with it eventually.

CCleaner will tell you every service being used, so you can just do process-of-elimination to find what you want frozen. If you want to free up system space (2gb is enough for me I just care about saving RAM) refer to the above list to know what's safe and what isn't.

I might upload a fresh stock rom if I ever reset my phone but for now it really isn't worth the trouble.

For the record, the phone is indeed snappier in doing all this, and this method works for any phone with any stock rom.