There are some songs that have voices in them that are meant to be interpreted as a certain character but these aren’t necessarily canon. Answered this here. 

It’s not really predetermined who will wake up first although Space players do have a tendency to be the first. 

Just agents and monarchs. 

Rose became Grimdark by becoming over-flooded by the powers of the Eldritch Gods.

Jade became Grimbark by being corrupted by the Condesce’s influence. 

Heiress Jane, presumably using the ecto-slime of Jaspers or one of Roxy’s cat clones

Caliborn had him killed

So that they could live forever in the dreambubbles instead of being erased by the Scratch

Time shenanigans

Flashsteping is just moving really fast, and the Striders are far from the only characters that can do it

Most of them can fly