A few points as usual.
1 WembleyFraggle, here's what we think might happen for the characters you listed in your post.
a. It's a very strong possibility that we might see Pops in the GMC spot designated as part of S9, though it should be noted that nothing's been announced as of yet.
2 Lips is a strong fan fav and might appear further down the road.
c. Lewis Kazagger, the Muppets Sports broadcaster, would be a bit of a longshot, but as Ken always says... Anything is Possible.
2 Zack, Ken said that the backstage won't come with the upright piano. Just no space for it in the set. Some of us have tried coming up with other ideas as to how we could get the piano, though.
a. Some have mentioned outsourcing a good dolls accessories catalog or store like GBU shops at.
b. Some, mainly myself, have suggested packing it with another figure like Nigel the Orchestra Conductor.
c. Another person suggested it be included with a front stage playset should that one ever be made.
d. Others have suggested it be made for a regular Rowlf variant to be carded and sold as part of the line further down the road.
e. But the majority of people seem to want the piano with a regular Rowlf variant as a possible club exclusive figure.
Hope this helps and have a good night.
Oh, and Zack, Ken wasn't sure as to the fate of Gaffer. In the Muppet Questions 3! thread he said that the cat wouldn't come with the backstage, but in the Muppet Questions 4! thread he said that nothing had been definitely said on that point.
Maybe this covers his bases for having the cat either with the playset or with the doorman.