Sorry he's not DE eligible for you. For the other guys here is some information to support that he may be worth a flier:
Neal finished last season as the third best 3-4 defensive end in pass rushing productivity. Only J.J. Watt of the Houston Texans and Arthur Jones of the Baltimore Ravens were more productive on a per snap basis than Neal, who tallied 20 total quarterback pressures (sacks, hits and hurries) over just 191 pass-rushing snaps." (PFF)
Clay Matthews: "Let's be honest. Mike's a freak. Most 300-pound guys aren't going to have an athletic frame like him. Now he moves as well as me or anyone who's an outside linebacker who's 240 to 260, and he's that much bigger." (JS Online)
Watch him chase down Alfred Morris and talk about how Matthews has helped him with the transition to outside linebacker:
http://www.packers.com/media-center/videos/Packers-Live-Mike-Neal/2ca17f1e-4174-4d40-8e7c-ec6515a98cdf