If you play as Two Tavs as a single player, doesn't that mean that second Tav will have a completely separate progression?
I mean, let's say Tav 1 goes to Shadowheart, kisses her on the cheek. Now I select Tav 2, does the same thing start over again? Does Shadowheart tell me; Sorry already seeing a Tav? I haven't done this in EA, I sincerely wonder how that'd work.
Totally different progression. As an early example, only one Tav gets the approval bonus for freeing her on the ship. On the other hand, if you want to romance two different characters, you can pretty easily manipulate relationships by having the unimportant Tav make the decisions that impact relationships.
I.e. If you are going to piss off SH with a decision you really want to make, like opening a particular chest, the Tav that is romancing Gale can open the chest with no damage done on the first Tavs relationship.