How much have you seen each of them play?
This is a good point, I have only been able to find a little bit of video on DeBerry, and even less on Piath and Mir, so it is hard to make many conclusions. Piath has a big body, a reputation for being fairly athletic, and supposedly can run the floor. Knowing just that, I would think the odds are decent she could be a good rebounder/defender.
The video in this thread on DeBarry doesn't tell me as much as I had hoped, because she largely is just using her height and mobility against far inferior competition. The one skill that stood out was her passing ability which looked quite good, for the other things I would need to see her against more talented players her own size.
I suspect that Piath needs to show something significant in terms of ability, if not playing time in her first year or she may be relegated to mop up minutes for her entire career, and could transfer. This year if healthy Geno could choose to use a three big rotation of Olivia, Aaliyah and Aubrey. Only one is a true center but I think Aaliyah can be a good if somewhat undersized backup to Olivia. Next year DeBerry comes on board, and the year after when Olivia departs, Brady arrives, and of course we are still in the hunt for Betts and other bigs.
If everybody is healthy and stays, Piath may need to be better than one of those players mentioned to get significant playing time. On the other hand as a possible specialist for certain match-ups, where a bulkier player that can bang a little would help, that could be a role for her. Olivia and apparently DeBerry as well are relatively slight not bangers. Could Piath help against a Boston on South Carolina for example?