ESO: Morrowind - Question on the current state of the 5 houses

What would be the status of the 5 houses going into this DLC?

I saw that a couple years before this a couple houses were fighting, but I wanted to know how these houses should be interacting with the Tribunal at this point in the history of Morrowind.

Who's plotting or at war with who?

Who's the most dominant house?

How receptive would they be to the entire mainland continent flooding their shores?