I agree with your post except the bold part.. According to me Dev (2) = Ishwari; Soha = Dev (1) and Jatin = Sona. In short Soha is to Dev what Dev was and is to Ishwari.. just like Ishwari didn't like when Sona made Dev happy. Dev doesn't like to see Jatin as a reason for Soha's happiness.
the comparision works two ways...
if you see Dev as someone who is genuinely making attempts to win and make space for him (he is the new member in the relationship) then jatin = ishwari and dev =sona
If Dev starts to behave all insecure and obsessed with Soha just because he is her biological father and demand that jatin be removed so that he can have an exclusive bond with soha... then he will be just like ishwari
so lets see which path Dev will choose ... will he chose to win over soha with the help of Jatin or will he chose to demand haqs based on blood relationships and completely remove jatin