As much as I don't find GM's character in the show admirable, Adi dying would be the worst thing to happen. As it is, Imlie is hung up on her BS. Not to essentially reunite with him..but to 'save' him from Malini and to remove all misunderstandings about her and Aryan (bring him down from beeg idiot stage to small idiot stage). Her love for him is intact..(love + respect + duty) . If he dies, she would don an extra layer of sacrifice..and basically make an altar and cry all her life in regret. Even if Aryan is beside her, she would be guilt tripped into a life of misery.
Him being alive is necessary to fuel her forward and to eventually show her the mirror on what was right and wrong.
If Malini 's pregnancy is indeed true, I think she would lose her marbles. Getting back Aditya was the sole reason behind all her actions. Plus that mother of hers would not leave her in peace. She might even force her to abort the child. Though Malini would not want to. I don't think she would be in touch with the Tripathis anymore ..maybe even move abroad.
As for Aryan, I don't think Aditya's death would give him closure ..as he would be tormented by the sight of Imlie. But he and his family wouldn't let her go easily. The mentor cum confidante position will be permanently his. Never know, maybe Imlie would shift some of the blame to Aryan..and leave Bhaskar Times.