The fun will never end. The sub is going to continue much like other fallen cartoon oriented subs. /r/TheLastAirbender, /r/regularshow, /r/gravityfalls and many more. We plan on still doing events, rewatches, discussions and whatever else you guys want to do to celebrate the life of Adventure Time.
Spoiler tags will be needed for at least another week because there are other outside of the US who still haven't had the episode air. Unfortunately its not practical to wait forever so after another week, visit at your own risk.
Rules might be relaxed in the future but as of now we are still keeping unofficial streaming links off of the sub for the foreseeable future. We'll be more lenient with shit posts now though.
Just saying, the Lich's spirit is probably dead because Sweet P is wielding Finn's Night Sword.
The cursed blade destroys spirits. Perhaps when he was older there was a major event in which Finn mentored Sweet P to be a hero. Part of that involved battling the monster trying to wrest control from him. Finn might have given him the sword under the guise of, "Do what must be done for the good of everyone"
I bet Sweet P, like a badass, stabbed himself to kill the Lich for good. In doing so he survived the impaling, and lived on to become a great hero Lich-free.
1 Ice King 2.0 or Ice Thing is still being treated with respect. I was worried people, especially Marcy, would ignore Ice Thing after Simon came back. But they don't. They befriend both of them as shown in the ending song when they are watching his puppet show.
2 PB now views Finn as an equal. For a long time, Finn has felt that PB looks down on him. He sings he is worried about this in What Was Missing. Its a running fear he has throughout the series. This fear is shown in episodes like King Worm and in Finn's vault in the finale. I think to an extent she did look down on him. Like in The Thin Yellow Line after Jake messes up, PB assumes it was Finn and says "What the heck Finn". But at the end of the finale, there is a great scene where PB thanks him for disobeying her. And comments on him getting taller (ie aging).