Yes, Om knows she is not his wife, Sia because he seems to have killed her in a fit of rage because he thought she was unfaithful to him. He must have found Tara in his hospital or he may have taken her to the hospital himself. Since Om seems to believe that nothing comes free (going by his taking kidney in exchange for eyes), he has given Tara her life and taken her identity.
Pre-leap Tara always took pride in her identity. She often referred to herself in the third person - Tara Bacchu. Post leap she is not allowed to tell the world who she really is.
Pre-leap MJ always took pride in the fact that he took all decisions about his life - whether to take the blame for his brother and face the noose, or fight against the evil or for his beloved wife. He never stooped to his uncle even though the rest of the family either feared or revered him. Post-leap Balli has been made a puppet in Kala a.k.a Laddo's hand. He takes orders from her.
Mriara's journey back to themselves will hopefully be interesting if handled well. Fingers crossed.
👏 very well written
Old EBI was about MriAra finding their way towards each other
New EBI in a way is MriAra rediscovering themselves and each other.