I think I mentioned this before, but if there's going to be a lot of minor Muppets appearing ( perhaps in crowd scenes etc... ) I strongly suspect that for reasons of time, budget and pure logistics, many of them will be CGI reproductions dropped into the shot. I hope I'm wrong and that they have indeed gone to the trouble of rebuilding lots of old, obscure characters. Yet something tells me that the cheaper option will have been taken, particularly if the characters in question are unlikely to be used again.