Piggy's Imagine Spot. She's a total diva, and former Vogue editor, but all she's really after is the proverbial house with a white picket fence, a couple kids, and growing old with Nice Guy Kermit.
The fact that Kermit joins in during this part of the song. It's a huge hint that secretly, he wants the same thing she does.
"We'll grow grey and old, and live the quiet life, just you and I..."
The other Muppets get in on the song as well. While the lyrics are disheartening, it's made clear that it's from splitting apart and being left by Kermit, not the marriage. In fact, they talk about how they should be excited for it, even calling it the happiest day of their lives or it's their dream come true. If it were Kermit going through with this, it really would have been a wonderful day, for all of them.Sadly, it isn't Kermit going through with it.
When Nadya comes to arrest Kermit for having escaped the Gulag with all the inmates, Walter steps up and apologizes to Kermit for not noticing that he'd had his identity stolen, then tells Nadya that if they take him, they'll have to arrest Walter too. Fozzie, Gonzo and the rest of Kermit’s friends follow suit, offering their hands/paws for cuffing. Eventually Nadya relents, declaring Kermit was right; they are his family. He thanks her by taking the Muppets to Siberia for the movie's final number.
Gonzo, Rowlf, Scooter and Miss Piggy apologetically admit to Kermit that they convinced themselves Constantine was Kermit because he gave them what they thought they wanted, but what they really wanted, nay, needed was the actual real Kermit.
That Walter is the first one to really realize that "Kermit's" acting weird in the first place, and is more worried about the shows going well than getting to do whatever he wants on stage.
This:
Kermit: Piggy, I'm sorry I ruined your wedding.
Miss Piggy: Oh, Kermie. (Piggy hugs Kermit) I'm so glad you did.
Think about it for a minute: Miss Piggy, diva extraordinaire and wannabe-bride to Kermit's groom, is actually thankful that Kermit ruined her big day, given she almost tied the knot with the world's most wanted criminal, and was almost killed at the alter.
Sam and Jean hugging each other at the end of the film when they realized that they would be going on their own separate ways.
How Miss Piggy figures out which frog is Kermit and which is Constantine: she asks them both to marry her. Constantine answers with a straightforward yes and rushing her along, and Kermit...
Kermit saying to himself that Piggy looks beautiful in her wedding dress.
Although the prior movie was fictional(?), one of the Broad Strokes remains: Walter has gone from Ascended Fanboy to the only Muppet who can act as The Heart when Kermit can't.
Notably, while the crowd at the prior movie's end was extras, when the Muppets head on a world tour, they get packed houses, showing that they indeed still have adoring audiences. While it turns out that Dominic has been handing out tickets for free, people got them in droves nonetheless.
Hell, ignoring Constantine throwing himself over the Moral Event Horizon with this whole plan, the amount of excitement "Kermit" and Piggy's wedding gets from their crew and audience is simply adorable, and Piggy herself is taken back by the proposal...until Constantine ruins it.
