Being under the rule of the Spaniards in Mexico was no ball of fun, but then again being under the rule of the Aztecs (if you weren't one) wasn't either. I'm not qualified to judge the details.
For sure not. And if I would be destined to be sacrificed to one side, I probably would prefer being a badly treated slave for the other side. But in general I likely would have prefered to have no more Imperial master.
If you ask the descendants of those people, you might get a different answer.
Because even the highest ranking "natives" in the new order were still lower, than the lowest white conquisator.