It's not Disney.
These stories don't all end happily ever after.
In true Brothers Grimm fashion, and in true Muppets fashion, there's a nonzero chance of key characters ending up eaten or exploded.
And it's perfectly lovely that way. This is the way Muppets is meant to be.
I think this book is meant as a readaloud by someone who has loved Muppets from The Muppet Show days to their children because of the use of some of the more obscure characters, like Wayne and Wanda. Uncle Deadly gets a number of roles. So do Janice, Sam the Eagle, Sweetums, Rizzo and the other rats, Animal -- it's not all Kermit-Fozzie-Piggy. Camilla the chicken gets some surprise leads, like in Cinderella, although Muppet language rules still apply. Camilla only speaks in bawk, and when penguins have lines that you need to understand, there's a 4th-wall-breaking editor's note that it has been translated from penguinese.
A healthy dose of the good versions of the Muppets is part of raising your kids right, and part of that in this case may be a rewatch of Muppets Tonight (I'm pretty sure I have taped-from-tv VHS of it somewhere at my parents’) and Muppets Christmas Carol to explain why Andy and Randy got drafted by Miss Piggy to play the ugly stepsisters because the Cratchit girls had a gig in Reno. There are enough contemporary references to make me think this might not hold up through the years, but also to make me wonder what I missed by watching Muppet Show years after the fact and to want yet another rewatch.
So, read aloud. Use character voices. Let it get silly. I literally LOL-ed when Beaker, playing a baker, was asked for some sugar by a monster. Beaker “Meep"-ed meekly and hugged the monster. This is the good Muppets (and not all of Muppetdom qualifies as such). Jim Henson would be proud.