Edea didn't freeze Squall and the others, she injured them. At least one of the spells she used in that scene is one she also uses in battle, and is called Maelstrom. She was just attacking them with magic, and the like, and them holding themselves and being still is the best way it could be animated.

I'm not sure if Rinoa's force field has any storyline explanation or not, but also keep in mind that she was the only possessed sorceress that split into many images of herself while possessed, so maybe she wasn't possessed correctly? She may not have been an actual sorceress until she was possessed, but I will confirm that with another thread. It could also be because she was the only one we saw being possessed from the start though (i.e. maybe Edea and the others went through the same thing when Ultimecia possessed them?)