The Jazz could actually run a really good 8-man rotation which is the way to optimize the contribution and chemistry of a team's most efficient players.
However, that should be for the playoffs. We need to keep guys fresh for a long season and it's an opportunity to develop depth which we'll inevitably need to dip into. So we need one more player, at least. Niang should not be that 9th guy, or probably even the 10th, IMO. I don't see why Oni would suddenly be ready after the shortest, weirdest offseason ever, so he shouldn't be either.
On the other hand, that slot is the only chance to try to develop anybody at all. Still intrigued by Brantley/Morgan.