It's funny how that happens sometimes. I used to have a bunch of platy fry in with lab, greshakei, and socolofi fry and they all did fine together. I know it wouldn't have lasted forever, but I was surprised at how long they did last before I bought more fry tanks.
I also had a few left over community fish that ended up sharing their tank with mbuna for a very long time before I moved them out.
This was one of two Abramites headstanders that used to be in the tank. I eventually moved them out.

And here's my oldest fish; the first fish I bought when we moved to Washington over five years ago. A blue gourami and I still have him.

Keep a close eye on that mollie. You never know when those crazy mbuna might decide they've had enough.