In a vacuum, his position classification probably has more to do with defense than anything else. He can play the 1,2, or 3 positions offensively and he's going to be a primary ballhandler most of the time he's on the floor regardless. Body type wise I would expect him to settle in as a SF but then if you look at the talent distribution in the league right now, who are we really worried about guarding at the SG position? There were only 6 SGs who reached the 20ppg mark last season and 3 of them play in the Eastern Conference. Most of the tougher SFs to cover (Lebron, KD, Paul George) are spending a lot of time playing the PF position these days to stretch the floor and get an extra shooter on the floor. Nobody is playing man to man defense anymore anyway so his role in the defense is going to be largely the same whether we call him a SG or SF.
We also have to find minutes for Buddy Hield and Bogdan Bogdanovic and that's going to be the bigger factor for us. With Fox at PG, Buddy or Bogdan at SG (with the other coming in as a supersub) we'd be playing Doncic at SF but he'd be sharing PG duties with Fox while they're both on the floor. Assuming Fox can improve his three point jump shot to the point where defenses need to respect it, we're looking at elite shooting on the wing and a decent shooter at PG. To follow the trend we'd get 1 big guy who's limited to the midrange and in (Giles?) and the other needs to be a guy who can space the floor (Skal?) or potentially a defensive specialist who can guard the 3, 4, and 5 positions and hopefully knock down open shots.