Could he do like Austin did and play high post while Mika was low post? I don't know what kind of passer he is. He seems like he has the touch and mechanics to hit that 15-20 foot jumper consistently.
I know what you are talking about with coaches seeing only height. You have to look at the personality of the kid, because the personality is not going to change. Neilson does not want to bang inside. Kaufusi does. That's fine. Just don't try and make Neilson what he isn't.
If I were Neilson, on my own I would be doing a lot of strength and conditioning this summer and come back next season as some kind of Josh Sharp/Nate Austin/Wiltjer hybrid. Maybe develop a double-pounder drive where he could rise from the FT lane or baseline and hit a jumper over a smaller guy. Fill that Sharp role of crashing the offensive glass.