I would be very surprised if either Harper or Owens is brought back next year, even on Two-Way deals. Harper is too small and Owens just sucks.
I hope Bolden is retained though, I'm a fan already. He brings more than Diallo to the table. Keeping him would make sense based on what both Monty and James Jones said about filling that roster spot as well. They said they're not looking for a rental or short term bandaid, they want someone that can help now with the potential to stick around and be part of the team going forward.
Just to note, Bolden is in his 2nd year and as a 2nd year player he is eligible to be signed to a Two-Way contract next season, if he and the team decide to go that way. We'll see what happens there. I'm glad that's a possibility still. If a player has played in less than 3 seasons they can sign a Two-Way deal.
CBA FAQ on Two-Way deals, for reference on that less than 3 seasons.