You just made Sanders case because everything in your post requires collusion on the part of each NFL team. That is the heart of an anti-trust case. Remember MLB has an anti-trust exemption, the NFL does not. I never said Sanders would be wise to do this, I only said he'd have a good case.
Not necessarily. A jury looking at the facts of the case, i.e. a first round rated QB fails to get drafted until the fifth, could reasonably conclude that teams would have had to collude for that to happen, whether or not they actually did collude. This is somewhat similar to the Kaepernick case. In that one the NFL reached a settlement. They would also settle with Sanders if he brought suit because the one thing the NFL doesn't want to do is lose an anti-trust case where damages awarded are automatically tripled.