What i think is, Vidyut will Kill Juhi and it will be illusioned as Mishti did it. That will compell Avni to take her blame for her obvious reasons. She will be trialled for same and Neil will be left devasted after this. He may also Beleive that Mishti did this and Avni again chose her Past over his Love by chosing to save Mishti. So that will explain the separation.
Now Vidyut will brainwash Mishti that she killed juhi and Her Angel is suffering and is away from her coz of the same reason. He may be shown reformed in outer demanour and may be grateful to Avni for saving his Daughter, just to show off. But deep down he is still the same.
His main motive is to still keep Avneil separated and for that he'l have to break communication between them and the best way will be to keep Avni near him and have a watch on her. That will explain him bailling her out showing fake guilt and reformation. Avni being Avni will refuse to take his help and accept to live in his house. Here Mishti will be used as a pawn. And for Mishti's sake she will agree and anyway she will be heartbroken coz of Neil's assumed Mistrust.
After leap, Avni is in Vidyut's house along with Mishti. Vidyut is doing everything to keep her away from Neil doing Aag me Ghee dalne ka kaam. And who knows in the process he may actually fall for her and really get reformed while Avni somehow discover his truth.