Cories should be fine with them actually...plecos though will most likely eat them. I've always had cories with my fry, they help keep the tank a tad cleaner from extra food since they can eat what is too big for the babies...and you know how hard it can be to get food small enough for them, eh? lol
Cories are fine, Kuhli loaches MIGHT be ok, it's iffy with them though since they're both fast and happy to eat young critters. Snails are certainly fine so long as you don't get those assassins or ones that hunt. =P Mystery snails are fine.
The only thing you have to worry about with snails or cories, is them eating the dead or ones that cannot move, but they wont hunt them down usually. I have some videos up in the video area of emerald cories with molly fry, they mobbed it off of its own food. =P I've also kept Julii cories and Schwartz cories with fry, the schwartz cories are the least good choice on them. I had a group of them hunt down all the new fry that were born in my main tank...the emeralds left everyone alone.
