To which candidates will NBC feed the questions in advance?
I don't know; but I think at least 20 of the 26 will be able to easily come up with answers to questions like:
How concerned are you about the reckless policies of DJT on women's rights?
How happy will you be when DJT leaves office?
When you defeat DJT in November 2020, what will be the mood at your campaign headquarters?
How excited will you be when you sign the climate accords?
etc
I mean, not just softballs, but mushballs.