The paranormal squad! but in kindergarden xD

I like the idea of Zim and Tak coming to Earth earlier and being forced to work together despite hating it.

I see it could be like a training process and punishment for both of them. Brains sees great potential in Zim and Tak, but their continuous fights cause a lot of destruction. That's why they get sent to an unimportant planet to invade before DOOM 1 starts to check if they can manage the given task or die. Either way, it's a win-win for Armada.