How long before Not So Fast Bucko?

So, there’s a necessary point toward the end of my novel where it looks like it’s all over. The evil chancellor is dead, the true king is in charge, and it was all a bit anticlimactic- all the main characters did was to show up and set things into motion- but no one’s complaining. So I really liked the idea of the main characters celebrating and discussing what they’re going to do next. The mood is fun but bittersweet, since they’re going to part ways with their friends. Some of their plans seem like clear Sequel Hook material, which is a nice bit of misdirection.

But I’m not sure how far to take it, since all of their plans are going to be moot in a day or so when the real villains of the trilogy reveal themselves. So how far should I let it go? The reader is going to suspect that there’s something going on because the victory was too easy and there’s still more pages to go, but at a certain point, I’m doing this sequence more to develop the characters than to fool the readers, but it still feels like it could get tedious and unnecessary to lay out these plans that never happen. Any advice or ideas on how to handle this situation?

Personally It sounds just fine for me, If I were reading your novel the emotional impact would be quite the blow and therefore if I liked your characters I would want to keep reading to find out what happens next.

If on the other hand you want to soften the impact add foreshadowing but depending on your audience you should vary your level of foreshadowing for instance extremely genre savvy people will find the smallest bit of foreshadowing and act accordingly (even if you were not upfront about the novel being a trilogy) larger foreshadowing however means that you are going to pull something even more unexpected (depending on how you do it, ps don't insult peoples intelligence).

Also remember this is your novel, If you have to do something that is unoriginal do so your way. Do not be original just to be original as it tends to alienate people no matter if you do it right or wrong.

Hypothetical, for example, other novels you have read have had dragons that was boring so you made your dragons centaur-ish. Think to yourself would this make your creatures weird and uninteresting or weird and interesting to your audience? because chances are people are still going to think it is weird based on their culture (literary culture especially) and experiences.