My hubs & I foster & we try to feed our babies something that can be bought at a grocery store or ordered... We feed the the infants KMR, but not step 2... When their teeth start to pop in the front I mix a little canned chicken kitten food (Science Diet Kitten Chicken & Liver) with the KMR & use an emulsifier in order to continue to bottle feed (we call it kitten mix). Incidentally, we do our best NOT to syringe feed, but will if necessary. It is easier for us, and I think better for the babies for them to suck a bottle. I allow them to eat as much as they want, to basically fall off the bottle.
At 5 weeks (or maybe 4) depending upon their abilities, health, etc we start them on the 'kitten mix' in bowls. We also offer (and keep in their 'houses') water & hard food. The hard food we give them is a mix of Purina Kitten Chow & IAMS Kitten Chicken. We don't ever feed them any seafood. The main reason is the smelly poops, but also it has been my experience that young ones (below 12 weeks) get really upset tummies with seafood flavors. Our babies don't know any difference!
In addition, if they need it, we add Fortiflora Probiotics to their food. We ALWAYS do this if they are on any antibiotics or have diarrhea, or are 'off' their food. I keep a close eye on my babies because they can go down hill pretty fast if things get side-ways without intervention!
I hope this helps?