They gotta go with a wing with their first pick since neither Isaac or Tatum will be there at 10. That means they have to take whichever of the Smith, Ntilkina or Monk trio is potentially left at 10. I'd probably take Isaac, but seeing what will be left at 10 I think they're going to go with Tatum as they will value his offensive game, over waiting to see if Isaac can develop into a scorer, you know Tatum will probably be a 20ppg scorer in his career. The 10 spot just becomes a case of going with whatever between those 3 is left, ideally you want it to be Monk or Smith as Ntilkina is going to take some time to develop and he may never be an offensive force like Smith and Monk have the potential to be.
I wouldn't trade the 5/10 for Fox either, the Kings need all the picks they have this year and next since they will lose it in 2019.