Speaker Choice
I think you are doing the right thing by getting components for the fronts and coax's for the back. I am wondering about the decision to put the tweeter on the door panel, next to the power mirror button.
Ideally, you want the distance between the speakers and you ear to be as close to equal as possible. This is the reason many people put speakers in kick-panels. Additionally, you want the sounds from each speaker to hit your ear at the same time, else the music might sound a little off. Since sound from both speakers travels at the same speed, the sound from the tweeter will hit your ear slightly before the sound from the mid in the door.
Component sets are designed for the speakers to be placed right next to each other, maybe we should trust the technicians.
Also, while testing the speakers out in the store, try to see if they sound as good off-axis as they do while they point directly at your ears. If they sound great at an angle close to the angle they would be while in the door, I think you've just had an easier install. Not to mention, if you put some holes in your door-panel, they will also be there on the day you (gasp) sell you explorer.
One last thing, if you end up putting the tweeter on the panel, be sure you turn the gains on the highs way down. Otherwise, you might want to buy some Tylenol from the stereo store also.
Go Broncos,
Karl Burns