cvella - longballz84 is right. Those are zoanthids. They should spread just fine eventually, but it can take a long time for a single polyp to turn into a colony. Or it could take a couple weeks. Different people have different sucess rates with them.
longballz84 - I usally do one shroom per plug, just because it is easier. I dont see why you couldnt do more than one, but I would let one attach at a time. Once the 1st is attached cut a 2nd and put it on. The reason I suggest this is that if you have alot of mushrooms cut in the same area it is easier for a brown jelly infection to set in. On the other side, if you were to do this there is a chance that the two frags could fuse together and you could get some really crazy colored mushrooms.
For your other question, it depends on what type of rics you are talking about. If you mean Ricordea florida, then yes, they are the same as discos and rhodactis when it comes to fragging. If you mean Ricordea yuma, then I would actually go so far as saying that they are a little more durable to fragging, if not just as good. Yumas have a somewhat harder center, which makes it harder to lose frags and they seem to attach quicker and better than normal discomas.