I dont understand the order of ancestors/dancestors and then current scratch characters? Shouldn't it be Ancestor > dancestor/descendent > current? It doesn't seem like thats the case or am i missing something?

I don’t know exactly what idea you’re getting about the Ectobiology chain but it’s like this:

Beforus exists. Karkat’s group are all adults on Beforus doing stuff. Meenah’s group are the group fated to play SBURB. They play SBURB, and lose. They realize their Session is awfully glitched- They came in riding on meteors, but they didn’t create themselves as is usual in the main Session of SBURB! So they know something is heavily fucked up. And so they reset- They Scratch the Game and start the Timeline anew, because if they didn’t do that, they would’ve never been born, and this paradox would cause a Timeline that’d just Doom them any way.

The Scratch shifts around the parameters, and so now instead of Beforus, there’s Alternia. Meenah’s Group ARE the Ancestors this time around, and Karkat’s group are the SBURB Players. And so, in the game, Karkat goes to the Veil and makes themselves, and their Ancestors- Which are, again, still just the Dancestors too. Sending everyone back in time through a Meteor Ride, which closes the loop of their Birth, and ensures there’s no paradoxes.