Agreed, I also think that she is involved with Lavanya. When in last week's episode Lavanya said to someone on the phone, " tayar ho, waqat aa gya hai". Then garvachoth activities started and prateek was with neha.
I dont think neha is behind all this.. Ryt now she is trying to become prateek's wife and rule that house. She may know who is behind this though. My guess is either Gaurav or Kushaan could be behind this. Gaurav looks like a big possibility.