I would say sure he can be trained as SF, but it will take a long time and training that IS will be a little painful. He has some similarities with the starting skillset that my SF has, Dwight Catic, who is about 120k salary and a three time Div II MVP winner.
He started with awful IS, and his weak guard skill was handling rather than passing. He was trained as a SG for the U21 team, but played as an outside SF. It was only after turning 22 that I started pumping his inside skills, which was a long, slow, arduous process.
So ultimately it's up to you, either way I'd recommend at least an advanced trainer if not a superior one, the choice would be between the easy path to make him a SG or even a PG if you were willing to invest more time into his passing, or the harder road which will mean playing him out of position a lot and your team succeeding at a slower rate. If you do want to take the SF route, it would be most optimal to train those inside skills first, but that would mean he'd be no chance of U21 as well, so that may factor into your decision, do you also want a potential U21 player?
Good luck to you, you have the basis for a great player there!