I'd give up a late first for him even without having Bird rights because there is almost no way a player drafted with that late first is anywhere near as good as Monroe. If it really was just Bass and the Clippers pick for Monroe, I would do that in a heartbeat. Monroe as starting center is a clear upgrade. I also don't think we would get any one better in the cap space this summer than Monroe, so see no issue with signing him to a 4 year, 50-60 million dollar contract.
And, TP - I agree with this post. Giving up a late first isn't going to kill us and, as you said, that player will be lucky if he is even a rotation player. If we really like Monroe, we can find a way to clear Wallace's contract - somehow. Also, maybe we can convince Green to opt in (we were nice to him, maybe he will repay the favor). It benefits him to wait a year anyway when contracts are supposedly ready to explode.
If Green opts in, there's almost no way the C's can afford Monroe, even if Wallace is completely off the books. Unless Rondo signs elsewhere.
If you want a team next year that includes Rondo, Green, and Monroe, the way to do it is wait until next summer, and then offer the Pistons the 1st and Wallace, who can be used (maybe combined with Faverani's non-guaranteed deal) to match Monroe's salary. Getting and keeping Monroe costs you the 1st, Wallace on the books at $3.3 million per year through 2018, and Rondo or Green (or maybe Sullinger, Zeller, or Olynyk if you trade one of them to keep Rondo and Green). No reason to give up the pick now for Monroe, when waiting until the summer offers you the ability to keep everyone you want to.