Abigail Williams and John Proctor had an affair. It seems like you are saying that Abigail conspired to frame Elizabeth and possibly other women. This would get Elizabeth out of the way and allow her to pursue her affair with John. Or, if this backfired, it would at least give her some revenge on John, who has decided to put an end to their affair. I think your thesis has to support or refute the idea that Abigail understood the religious fervor of Salem and knew they would react irrationally to the idea of girls dancing in the woods at night. Abigail conspired to start hysteria of witches in Salem, hoping to replace Elizabeth as John Proctor’s wife, or to get revenge on John for ending their relationship.
I think this is a good thesis, but I think you might have to say that it became much bigger than Abigail could have imagined. Maybe she did start this hysteria for revenge. Maybe she started it to get Elizabeth arrested so she could be with John. I doubt she could foresee how far it would go. That is something you probably should address as you support your thesis. It doesn’t affect your thesis at all but it would help to clarify the development throughout the play. Abigail started this thing for the reasons you’ve mentioned. But then you need to address if she planned the whole thing or if it got out of control. Abigail started everything but if it did get out of control, then others also at fault.