As to Parson and gang being displeased with Stanley: I fail to see what, if anything they can do to him. Yes, he left them in the lurch, and yes, they might dislike/hate/despise him for that, but I don't think it matters. As I recall from an earlier comic, all troops on a side are under a loyalty stat, which prevents them from betraying their alliance under all but the most extreme of circumstances. I don't think they'll be capable of acting against Stanley, once he returns.
A good example of this probably comes from Sizemore. He says he hates Parson for what Parson asked him to do during the course of the siege. Fair enough, but don't forget that Sizemore Did it anyways. He may have hated it, but that loyalty stat seems to have prevented him from doing anything but follow the orders he was given. I hold that the same principle will apply to Parson, Maggie and Wanda.