Welcome to the forum!!
Sounds like you are the one brainstorming the perfect low buck system here!
While I normally would not reccomend pyramid, lets work with what you have.
I can firstly say that it is safe to omit half the speakers from your install and obtain even better soundstage.
The rear door speakers and the rear deck speakers can go. In a properly tuned system, there should be no need for them. Plus, I will stake vital parts of my anatomy that the 4's in the rear doors will not be heard that well either way.
A side note, you are aware that the 6x9's going in the front doors will likely require modification to the doors sheet metal and door panel to properly fit. Unless you build out your doors, your 6x9's will probably not clear the path of the window and locking mechanisms.
On that note, I have likely placed a few thoughts into your head, so i will let you think on them and if you have any other questions, please dont hesitate to ask.
As for the bandpass, I believe that Orion does build a pre-fab triple bandpass enclosure, however, What specifically interests you in the bandpass design?
Ok, done twisting your arm......
(for now!
)
Take it easy,
-zane
