1- Xavier had blocked the vast majority of her power, so she just displayed limited telepathy and telekinesis. That was it. She was at a very early "Marvel Girl" stage at that point. Xavier was seriously freaked out by her "Phoenix" nature and level. Cyclops and Storm were powerful and skilled, but just "rusty" and "out of shape" (from a conceptual point of view). They had stopped training themselves long time before X1. In X2 (six months later), they were fine. 2- The continuity is super-okay. Deadpool 3 will be a metafictional superhero comedy, you cannot take that as canon (unfortunately). It's an alternate universe. 3- Famke was very fascinating. Sophie was more vulnerable and melodramatic. I think that the XCM Jean Grey was a constrained person, very afraid of herself, and that's why she (they) looked so distant and emotionally detached. You can see the change of Sophie's Jean at the end of Apocalypse and during the entire Dark Phoenix. Famke was marvellous in both X2 and TLS.