Totally pass on 2 & 3. They are not good at all IMHO for this trade. CMC would be great, but OBJ & a 1st is much too steep. I would keep OBJ and have a stack at WR. Look at adding to the RB next season. IMHO, you will either have Thielen as your top WR or Mack as your top RB, they are a push. Having CMC or OBJ does not will just make one stronger while weakening the other. If that makes sense.
I definitely think CMC is a great back and one to target, but giving up OBJ plus is not really worth it. Just my two cents, but in the end I am not sure how this trade affects anything unless you are just a bigger fan of CMC than OBJ. If that owner does not come down off of his 2020 1st throw in, I would bail on the trade.