Has anyone heard of the running gear of '85 F150 4X4 bolting in to '94 F150  2X4  

Nope,but 4WOR did a late '80's Ford 2WD to 4WD conversion a while back....the 2WD front crossmember is right in the way of a solid front axle.

1. Probably better off selling both and just buy a 4WD to begin with.

2. Rather than swapping drivetrain, it might be easier to swap the newer body on to the older frame. If you have both next to eachother take a few measureents and see, a slight body lift might help clear thenew body.  Body mount are easier to fabricate than transplanting all of the drivetrain into the newer frame.