how do I know if I uninstalled something I shouldn't have Epic sph-d700 rooted 2.3.6 kernel v 2.6.35.7 FC09

I wanted to free up RAM by removing some system apps. 

after removing 7 of them my system started having unexpected errors.

Google play updates wont install. 

Is this repairable with clockwork mod or Odin?
First of all, if you are not 100% sure which system apps you can uninstall, it is better to freeze them first (which is supported by e.g. Titanium Backup and other apps). So if something starts behaving weird, you can simply unfreeze those apps again.

As you probably haven't just frozen the resp. apps, let's move to the second option: You hopefully made a Nandroid Backup before starting to tamper with the system? In that case, you can restore this backup via ClockworkMod. Or if you at least backed-up those apps you uninstalled (e.g. with aforementioned Titanium Backup), you can use this to restore them again.

If this is no option neither, all what remains is to check for a fresh firmware image to flash -- either stock or custom ROM.