Disney's thinking with the non CG Muppets is very clear to me. The Muppets require only a fraction of the time and money that animation does. It's less of a financial gamble and it's clearer to predict movie trends one year ahead rather than three.
Subtract the budgets from the box office and it's easy to see why Muppets make good sense:
Movie/Domestic Total/Budget/Outcome
Smurfs: 142.5 – 110 = 32.5
Hop: 108 – 63 = 45
Gnomeo: 100 – 70 = 30
Muppets: 88.5 – 45 = 43.5
Plus, they have a built-in fan base that's a lot larger than Disney had realized. They want to grow this. With adequate marketing and a quality film, there's no reason why any future Muppet movie wouldn't make a tidy profit. And it seems that Disney has discovered how easy and useful it is to have these characters make public appearances.
The only really comforting thought is, while Muppets made the least amount of box office out of those 3 lousy films, it was low budget enough to actually make more money back than 2 of them. Plus, the Muppet puppets have been made and remade again for the movie, that means we have a LOT of puppets to wear out in other projects. I'm sure a lot of the Muppet movie budget was saved in older puppets that were in just good enough shape to use. I'm sure even in CGI, they need to refurbish some of the existing models to update their look consistant with the rest of the technical advancements in a movie.
Calling it - if this gets made, that's a Bill Barretta character.
If they don't go with just puppeteers that focus on work at Henson. I'm sure they'd use some of the Muppet/Sesame Street project puppeteers as well. As long as said puppeteers aren't busy with something else.
Still, the references to this movie being similar to Roger Rabbit only work if you say Roger Rabbit is similar to The Big Sleep (or some other Noir movie). Maybe closer to the book (is that even in print anymore? I'm dying to read it), but the only murders in Roger Rabbit (other than a few dipped 'Toons) were humans... Marvin Acme, Eddie's brother... This movie seems to have only puppets murdered (so far).
Still, how straight are they going to play this? To me, the project will be MUCH funnier the straighter they play it. If it's gag a minute and Greg the Bunny-like, it might work, sure... but not as well as if they make it as dark and gritty and realistic and CSI like, but with weird puppet characters there.