I would take Okeke if it was a choice. The possibility of a great three big rotation with Sarah and the Big O is intriguing. With solid options for a 4th and 5th big in Ayanna and Jana, and a development project in Gandy. When teamed with Olivia, Okeke can be the 5 on offense and the 4 on defense.
If she does well and warrants more minutes, it also covers the 3 position with great play for 40 minutes, because Sarah could be Blanca's backup there for a few minutes playing with The Big O and Okeke.
Part of my preference for Okeke, is I like the prospect of Sarah getting minutes at the 3 better than Blanca getting more minutes at the 4. Blanca can play the 4, but is a much better 3. Sarah is exceptional at either position, and amazingly good at the 5 as well, but I consider the 5 her least great position of the three.
Having players like Paige and Sarah that can play not just two positions but 3 or 4 at an exceptionally high level can solve a lot of potential problem areas. I'm pretty sure Okeke would be a two position player as well, maybe Nell too, but the 4 seems like a stretch because of her size, and the 2 not ideal because of her 3 pt shot. As a 3 she could be great, but that is best for Blanca and maybe Morgan as well, although she could be another 4 position player like Paige, but at a much lower level of course.