You're absolutely right about the soulmate bit! These two were and will always be each other's saving grace. No matter how short their journey together may have been, they built a world with each other where nobody else will ever be able to reach.
Even with all the mess in their lives, the sanctity of this bond will live on.
If we didn't know that HS was going to die we'd not have said 'how short the journey may have been', because in all honesty, I would think Minnie would come back into their lives at some point. I think the audience members who are not on IF or social media would have no idea that He would die (until they see the new promo) but there was something about this scene that had a finality to it that even those viewers cannot have missed, as if it were indeed farewell. Especially the way HS says no matter what happens you will always be my Veer Balika. That's the term he used for her since their first interaction and this might be the last time.