Canned/moist food that is easy on the stomach?

[InBetweenDays]

We two lab mixes, one of which had to have a tooth removed yesterday (it had broken off and they had to remove the root). He normally eats only dry kibble, but our vet said we should feed him soft food for two weeks. Last night and this morning I added some broth and heated up his kibble to soften it, but it took about 30-45 minutes to get soft enough to where I felt comfortable giving it to him (and being a lab he has a hard time waiting that long once I open the food container ).

I'm considering getting some canned food but don't want to upset his stomach with such an abrupt and temporary transition. He's already on Rimadyl (for arthritis from a bad leg he's had since before we got him), Tramadol for his mouth pain, and an antibiotic to prevent infection with the root. Any recommendations? Or would you mix up rice, ground beef, and cottage cheese? Or just continue softening his kibble?