Very nice and complex topic. It is hard to predict atm because it depends on how the chain of events will unfold.
If Dulli to happen then under what circumstance and how? Who advocate Dulli or Dushyanth himself? Like trifolia said about Dusyanth's reaction to Gulser how would Thalli feel knowing 2 men in her life were/are madly in love with Gulaal?
How Vansanth's mystery unfolds to the family? By whom? There is a chance of both elder brothers may face each other and Raman use this trump card to manipulate the situation and put Dushyanth on spot light. In that case it will be a treat to watch JK's dilemma as to which son to support.
The equation of not only Kesar and Dushyanth but Dushyanth and the whole family will change depending on how these events will unfold.
I don't think any of Vasanth's family will forgive Dushyanth so easily, they will just learn to live with it, maybe for Thalli and family's sake.
BTW-Given the current Dushyanth I don't think he will have vengeance for Gulser, he might at last be at peace given that Gulaal is happy. It could be Thalli who might have things against Gulser that she has to live seeing them.