Xavier Legette - I agree with Big Nate's assessment. Legette has the best opportunity to be the #1 receiver in Carolina, and that gives him a lot of value.
Adonai Mitchell - Mitchell has the highest upside of the group, but he might take some time to get there. He has a lot of target competition, so he might be a bit of a project.
Roman Wilson - Wilson has a chance to be the #3 or even #2 receiver in Pittsburgh, and that gives him some value. He might not do much in his first year, but he could be a solid contributor in the future.
Malachi Corley - Corley has similar upside to Wilson, but he might be a bit of a risk. He's a talented player, but he's not a lock to seize his opportunity.
Overall, I think Legette is the safest bet, while Mitchell has the highest upside. Wilson and Corley are both intriguing players, but they might not contribute much in their first year.