The Bills would love to have Clowney, but they need more players in the top 100 than just him. Here is a possible trade DOWN scenario involving Cleveland, leveraging the lovely connection with Pettine:
Bills give up their 1st and 4th round picks (9th and 109th) to the Browns.
Bills receive the Browns' second 1st, 2nd, and second 3rd round picks (26, 35, 83).
Based on trade values, both sides of this trade are worth ~1425 points (1426 for Bills, 1425 for Browns), so it is mathematically a fair trade.
This allows the Browns to grab their top WR and QB if still both available with limited risk, and they still have their original 3rd and now 3 4th round picks to grab other players. This is a huge benefit to them.
The Bills now have picks 26, 35, 41, 73, 83, or 5 picks in the first 3 rounds, with 3 in the top 41 spots. They won't be grabbing any of the super popular guys, but can still grab a very solid OT, TE, DE with those first 3 picks (perhaps Cyrus, ASJ, and Crichton), and then a solid DT and OG with the two 3rd round picks.
All 5 of these picks could easily be starters.