3WR's, 1 TE, 1 RB - yes, your base should be able to match up with that no problem.
Occasionally, maybe. The problem is now you're bringing a safety to play man to man against a (likely) shifty slot receiver. Or sliding out a linebacker. If the linebacker has the slot, that's where the ball is going.
If the safety slides down, a competent quarterback will push it deep. Single coverage, go/fade route. Again, this is a thing that makes a quarterback excited.
Worse, you've overloaded against the run when the offense comes out in a passing formation. Your alignment is roughly 8 men in the box!
I say I would only run the 2-4 in obvious passing situations, and give you an alignment, and the first comeback you all have is - "teams will run against us"?? That's my #1 complaint against the alignment to begin with - regardless of whether we're in the "fat-guy 2-4", or a "pass rush 2-4".
Again, this is the back and forth of football. ALL NICKEL FRONTS ARE EASIER TO RUN ON. That's the whole thing. Offenses want to throw against base, run against nickel. It's all about forcing the defense to do one thing so you can do the other.
If it is a run/pass situation, the 3-3 would be much more effective at dealing with the potential of either the run or the pass b/c you have more overall size on the field, and you have pass rushers.
Two problems with that statement. You presume that having more linemen will improve the run defense. It might make it easier to engage the linemen, but that's it. Drawing it up, I see more natural running lanes from a 3-3 than a 2-4/4-2. Assuming a relatively simple offensive alignment of QB under center, single back directly behind the QB, TE inline to the offensive right, flanker out right, split wide left, and slot left, where are you lining everyone up?
Second, you still haven't explained how we're going to cover the TE and RB effectively with a 3-3 alignment.
3) It is permissible to both blitz and play zone.
It is, but it's harder. If you rush 5 or more (the definition of a blitz) then you've created another natural hole in the zone.
Remember, (good) modern QBs
WANT to be blitzed. You've taken a man out of coverage and simplified their read a bit. Identify the blitzer, identify who his man should be, throw to that man.