@Anissa86
If your daughter in law is getting blocked from booking due to the party ban policy, I don't think there is a way to override that, but I could be wrong.
Out of interest, why are you even taking this booking on Airbnb? Airbnb is a listing site. You and the guest largely pay them for helping you find each other, which is not the case here, and the guest pays quite hefty fees on top (as well as some from the host). So, why not just block the dates and handle the payment yourself? The only possible motivation I can see for doing it via Airbnb is to gain good reviews, but that's actually against the Airbnb review policy... i.e. offering a discounted price to someone you know in exchange for a good review could be seen as suspect.
As for the other blocked bookings, I am not sure what is going on there. You would have to give more detail on the nature of the bookings, e.g. are the guests local? Trying to book an entire listing? Under 25?