This really is putting the horse before the cart, isn't it?
All hypothetical... let's say the movie's so successful that there IS a TV show and future projects. I can't see him having a major role, but I can't see him shoved into the background either. I'd see him somewhere second or third tier character about where Scooter or the Pigs in Space are. Maybe he'd have his own segment, maybe he'd pal around with Robin... it's too soon to tell, since we haven't even seen the movie yet.
As for Pepe, yeah. He came out of being a secondary/tertiary sketch character to fill in empty spots left by characters like Scooter, Rowlf, 2/5 of the Mayhem band... etc. etc.. to becoming the signature character of a performer. I'm convinced that's why Baby Bear became a major character, David needed his own Muppet to perform regularly. But the thing is, Bill is the official Rowlf now, and we're seeing a lot more of him in recent projects... and I wonder if that will diminish Pepe's role if Rowlf gets back into the spotlight.
As for movie characters in future projects... well, other than Polly and Clueless's UK only Muppets Tonight segment, they never added movie only characters to other projects (though they are also reusing some MTI pirates in minor bits). I do not count the Muppet Babies show, since something tells me that was going to happen all along, and they wanted to introduce it in MTM. But you never see Bill Gil and Jill outside of the movie (except for the racing video game)... and Spa'am never made an appearance outside either.