1. Yes, to question the F&DS is to question God himself. Their recent literature even states "you must obey the F&DS to have Jehovah's approval" They say jump, JW say how high and how far. (no joke that was actually said in a talk) It is rampant thru the literature how they equate themselves to God and Jesus, they speak for God, they are needed for salvation and that they are your mediator (Jesus is only the mediator for the 144K) The WT really is their god. They idolize the WT.
2. Yes the teaching can flat out contradict each other, make no sense, sound insane (overlapping generations anyone?) but the F&DS just toss it up to "new light" new understaning, even if that understanding was used before and rejected. Doesn't matter. You must follow that, see #1.
3. They must, MUST believe what they are told. If they don't, and it gets out that they don't, they can and will be DF, most likely for apostatsy. Failing to follow #1. Doesn't matter if you can prove from the bible the F&DS is wrong, doesn't matter if you can prove from the literature the F&DS is mistaken or lying. Doesn't matter. Death (DF) or obeideince.