I'd do the seperates, coax are a compromise.. at best..
highs radate in a straight line and the reason for "dome" tweeters
you want them aiming at the ears, within reason, the pro's make it happen, you don't need to spend weeks building a mount to place it in the truck..
in a standard cab truck you really can't get the tweeter far enough away from the mids to have an issue.. you'd have to put the mid driver in the kick and the tweeter behind your head to have a timing issue..
your truck I'd put the mids in the kicks and the tweeters in the upper door.(as that panel is replaceble if needed. kick panels that aim the speakers at you, then put both in the kicks.. tweeters don't like dirt.. so I don't like mounting them that low..
my truck was already cut so there is 6by9's in the rear of the door, 6.5's in the front of the door, 6.5" in the kick panels and the matching tweeter in the dash(beside the a/c vents)
once the tank is out of cab.. a single 12" sub will go back there and move the 6 by 9's to back there.. looks like you have no issue cutting (see dash) if you put the speakers in the doors, you may chase rattles.. and get the foam speaker backers to keep them dry
