Due to cliches We already know that Melvie is 95% gonna get saved at the last second by Fooly
I will however go further and state that Melvie is gonna realise that Fleur and Leo both got stronger because of their emotions towards Fooly and she's gonna develop some sort of obsession with him...
To clarify:
I asked the author personally about the nature and connection of this manga to the doujin and H images he does.
Turns out that it's all parallel universe spinoffs and there is no NTR involved so you can rest easy.