Eden, you are doing great!! And doing a wonderful thing keeping this little one safe and looking for help for it. Just a few thoughts, and responses to some of the questions you raised that were not "urgent response items" --
Chippies store up seeds and stuff in their pouches to bring back to their nests to store. when he spit out the seeds, that's probably what you saw -- he didn't want to hold them anymore.
Along that line, be cautious in giving him water on a cottonball -- just make sure he sucks or nuzzles, but isn't able to take the cottonball into his mouth/pouch. I'm not sure how that would work or if he'd be able to dislodge it.
Possibly he had something wrong with his eye and THEREFORE was vulnerable to being caught by the cat? It would be too soon to show infection goop from the cat.
Seeing where he seems to be hurt and how the cat was holding him, you should continue to be cautious about moving him so him injuries aren't worsened. You seem to have thought the same thing, but just thought I'd mention. GOOD news that he is moving his back legs, feet!!
I wouldn't worry about him eating anything just yet. He is injured and in shock. Keeping him hydrated is good, but he shouldn't be eating (like, if you went to the ER from an accident, no one would stop for a burger on the way, lol).
Just continue quiet and safe and comfy while you try to connect with a rehabber. Did IR give you multiple contacts to try? Perhaps we should look for others if this one does not seem to be reachable soon??