I expect both to stay for different reasons

First of all, I don't pretend to know what either of them are thinking, so it's all baseless speculation.

Put into context, if ND gets beat in the Elite 8 game, that would seem to incentivize Maddy's return. She clearly idolizes her big sister and if I had to guess, I think Kat would tell her to return and finish the job. Obviously, the ultimate decision will be Maddy's but Kat will undoubtedly have some influence. But the possibility of making a deep run next year has to be in her head. A byproduct of staying would allow her another year of development, which will only make her that much more attractive to the WNBA in 2025.

I could see Nat going either way on her decision, but her career path is potentially so diverse that it may not include basketball. I think the pull of returning for one more year will be stronger than starting new somewhere else, especially if she isn't seeking a pro basketball career. But if she is then it makes sense for her to seek options elsewhere.

I disagree that ND doesn't need a transfer, regardless of who's staying or leaving. I think people are making a lot of assumptions that Koval will be ready to play at a high level her first year. I think that's unfair expectations and frankly, unwise to pin a lot of your hopes that she is. Also, what's the contingency plan if she gets hurt?

Next year is a kitchen sink opportunity, where you need to put every effort into winning it all, because it will be the last dance for so many key players. They need to get the best center possible (with size and athleticism) and they have a lot to offer. My guess is that the coaches agree and will address this.