Dont you want your tweets up high? eg a-pillar, not down in the kicks?
As for sealing the midrange over midbass separately, yeh that makes sense.

Ideally yes but in a car the size of a Falcon the difference in distance between your ears and the speakers on the right and the left is a massive difference which makes the right side much louder than the left plus there will be a difference in arrival time of the sound because of this difference.
That is why for years now kick panel mountings have been utilized in comp cars as it gives a more even sound, despite the fact that the tweeters are mounted low if angled correctly it doesn't sound that way.
Also it is very desirable to have all the speakers as close together as possible so you don't a big delay between the different frequency ranges so using a midbass low and forward in the door and mids and tweeters in the kick panels keeps them very close together.......