I mean each class/aspect combo can be really powerful in their own right. In terms of raw power I think Jake or Jade are arguably the most powerful godtier titles. Maybe a Page of Space or Lord of Hope?

On this page he said he was mind-controlled by Vriska to troll her. 

“Being from Derse means you are from a culture of offense and aggression. Being from Prospit means the opposite. You could argue that these are qualities that either rub off on the dreamers, or they are designated as those dreamers in the first place because of those qualities. You could take the view that these are innate tendencies to overcome, as seemed to be the case for Jade and Rose. Or maybe sometimes they are tendencies that are resisted, and need to be understood and embraced. As a Prospit dreamer, did Karkat struggle because he was actually passive in nature, but had a very active self image as a leader and conqueror? Was Vriska an even more extreme case of misplaced active behavior from a Prospit dreamer? These are yet more things to consider when looking at everything contributing to the hero story of an individual in this game.” - Source.

Yes.

Jasprose says here that they recall the lives of many Roses.

Equius and Aradiabot

 Davepeta and Jade

 Rose and Kanaya

 Vriska and Tavros

Roxy and Dirk 

Dead Roxy and Dirk

(Vriska) and Meenah

Sollux and Feferi

Rose and John

Dave and Jade

Karkat and Kanaya

Terezi and Tavros

Dirk and Jane

Dirk and Jake

Spades Slick and Sn0wman

John and Gamzee (?)

I think thats it…

Jasprose says here that Karkat is in a matespritship with someone on the meteor and Vriska says here that Karkat was very cagey about his romantic affairs. Also there’s this vine of Hussie confirming davekat. 

Yes, Equius is a vegetarian. On this page he says that animals are for admiring only. 

Yes, the aspect Time is associated with many themes of progression and inevitability. It’s also associated with death. Dave has an interest in dead things and so does  Aradia with her archaeology. Lord English is the embodiment of death in troll culture. If you want to learn more about Time check this page. 

On his introduction page it says he likes to collect dead things preserved in various ways and he mentions paleontology specifically here.