I would train his outside skills the whole season if possible and then make him a PF later on. IMO "At Div 4, how high should those be (minimum)?" is the wrong way to look at it, these skills should be as high as possible. Something like OD 7 DR 5 PA 6 would be a good goal for this season. In fact I would like outside training to continue in the second season as well but that is probably too future oriented for many people.
If your goal is to increase his value if you decide to sell him, probably just getting PA to 3-5 and then working on his inside skills is the way to go.