Great suggestions, rarmes. Since this post is from Aug, I assume all your little guys are long gone but here are a couple more suggestions for future kittens.
For fearful, squirming kittens try hand feeding them their wet food and treats. Also, handle them often but briefly. In a quiet, calm space, pick them up and hold and stroke them until just before they start struggling and then gently put them down. Don't put them down if they are struggling b/c then they learn that if they struggle you will let them go (think about how this lesson will effect vet visits, for example) This may mean only only hold them for a couple seconds at first but that's ok! If you wait too long to put them down and they start struggling, apply gentle pressure (if that is calming) and wait for 1 second of stillness and then let them go immediately. Frequent, short socializing sessions like this will give them many opportunities to realize that you aren't so scary after all.
I had one kitten that was more scared than the rest. When I let them out of the cage, I held the scared one as described above before I let him out so I was able to reward him with freedom for allowing me to hold him.
#FosteringaPet