To answer the question, yes, Williamson for Brown is a trade I would "so". There are not that many I would trade Brown for, Williamson is one of them (the rest of the trade is far less consequential).
No chance that NOP does this in my opinion. Now maybe if they fear they will lose Williamson but he is an RFA next. They have him tied up for several years. They don't need to do a "cut your loses" trade for at least 3-4 years if not more. Club option in 2022/23 and then an RFA in 2023/24 where they will no doubt pay the max that anyone can pay. I am not sure there is a way for Williamson to get out unless he flat out refuses to play.
It is really too bad for the NBA that this type of thing even comes up.