Points in favor of Smiling Friends being actually over:
Zach and Micheal have stated they want to end the show on a high point and don't wanna drag it out too long.
The announcement vid was clearly very genuine and off the cuff
They straight up said this was not a gag or a joke and that the show is actually ending.
Adult Swim seems very flexible with the two creators, so it's very likely they're chill with them backpedaling on already confirmed seasons so long as nothing has been started on them.
The two bonus episodes of season three were likely made when they decided to cut the show early, as a way to give fans one last thing to look forward to even after the show has ended. As noted, AS seems very flexible with letting these two do what they want here.
Points in favor of this being an insane April Fools joke:
The episodes are dropping officially in April, when they likely could have been dropped sometime in March or even this very week.
Adult Swim is known for insane April Fools jokes, plus Zach and Micheal are accomplished shitposters.
Episode titles and descriptions have straight up lied before.
Each season was made on an 8-episode order (even if the Brazil special is considered S1E9), so it feels odd that season three just so happens to have extra episodes, and two more at that.
Specifically making an announcement video is inherently more suspicious than just posting that it's over.
Seasons four and five were formally announced.
Saying in your video that "This is not a joke" is the quickest way to rope people in on this being a joke.
Again, the Hadel-Cusack event horizon is insane here. There's genuinely enough evidence that this could be an elaborate gag or a genuine cancellation. It's really just a matter of time.
