BAe146 ended up needing 4 engines, due to the required thrust level and availability of powerplants (as I understand it). It's a challenge to fit 4 engines anywhere except on the wings. (VC10 Jetstar notwithstanding).
Once you decide to put the engines underwing, you're forced to consider ground clearance and FOD issues, which tends to drive the wing upwards. Essentially, the bottom of the engine cowlings has the same kind of requirements as the bottom of a prop disk would have. So if a "prop 146" would be a high wing, chances are so would a "jet 146".
Bear in mind that wing position is a compromise amongst many, many factors. You can't just burn it down to a couple of factors. Even things like "design habits" of a particular design team plays a part.