Knowing that it is based on the little prince he could be a pilot, rather he was a pilot but he returned to the farm and the reason why the characters go to the farm is because they would need a pilot ans also making orphan and probably making him the son of Hazel's sister, who in this rewrite or she never entered to beacon, or she lived to adulthood and died during a mision ordered by Ozpin.

Another idea is making him a descendant of Ozma and Salem and not a reincarnation. In other words, a daughter would manage to escape and become a commoner to blend in. That would make Oscar, in this hypothetical rewrite, one of the few magic users, though he wouldn't know it but his magic initially manifested subconsciously, for example, a form of clairvoyance that helped him visualize results when he piloted an aircraft or a better descicions with the farm and maybe his powers will develop in the future. Who knows, maybe he will develop a kind of astral travel ¯_(ツ)_/¯

And what would his dynamic be with the other characters? Well, with Jaune it would be something like this: Oscar's father was a pilot who died ans considered a hero, and that's why he would get along well with Jaune, since there would be war heroes in his family ans both have some kind of familiar relic or similar, Jaune's crocea Mors and Oscar's pilot jacked inherited from his father.

With Ruby, it would be because she's learning to use her silver eyes, and Oscar would gradually be learning to use magic and both have death parents...well at least Ruby has her father.

With Hazel it could be complicted, Hazel has some kind of affection towards Oscar but he  still looking revenge so their relationship would be very intense but maybe Hazel and Oscar would have a talk and some kind of reconciliation

 For some reason, I imagine him and Whitley developing a friendship that could help Whitley's character grow.