Speculation wise, it can change, but your pointers make sense. It falls in place.
Viper will definitely NOT give up. She is desperate. By the end, Raya will know how she tried to separate them from the beginning of their marriage. The thing is that "pull or kheechaoon" between Ram and Pri is enough to pull the mask from Viper's face.
I think vedika will be the one who will discover nandini and shashi's involvement in sn. Kapoor's death. And will use leverage that over both of them.
If vedika is using MS next to separate Raya it's a matter of time before she gets to know about shashi's involvement and somehow i think Nandini is also involved that's why she always favoured shashi even when he went bankrupt.