Please remember these are college kids, with full lives. Arike mentioned in a post-tournament something to the effect that she "isn't just a basketball player. Basketball is just something I do".
They work hard and dedicate a lot of time to their sport. Why not have some fun and enjoy a special opportunity. It would also seem to have benefits for women's BB, ND BB, and her future marketability.
One of them during Finals Week.
How much basketball prep do you expect during these 4 weeks? It's not like the coaches can work with the players and there are regular practices.
The timing is fine for this, IMO. Summer session doesn't begin until Jun 18 (It will be done by then). Weight lifting most likely won't be affected. If anything, the dancing stuff might really help even more with keeping her in shape. Those routines are rather rigorous.