IMO, Harper and Brown are the only true locks to get drafted. The NFL will like Harper's versatility. While people may look at a 230lb receiver who doesn't have a ton of productivity they will see his skills as a runner (Oregon QB) and ability to run the ball from receiver position, blocker, and he does present some skill as a receiver though not quite that steady by NFL standards. He may be seen as a unique 3rd down back as a receiver out of the back field. Honestly, someone may draft him as a running back and primarily as a receiver from that position. Either way his complete skill set has some value.
I think there are a handful of players who very well may get drafted and that would include Malone, Wilson, Klein, Tuggle, and...yes, Tannahill.
As for Meshak Williams and Adam Davis? no. Meshak has a limit to his size and he's too rigid to play the OLB position in the league. Adam Davis would have a shot as an OLB if he were more explosive and had more quickness to make plays in space. Neither will be seen as an NFL prospect. But they are quality defensive ends for us in our scheme and what we like to do.
Tuggle and Klein are the two guys that will really intrigue scouts. Tuggle has some upside to play in the league. He is explosive, that was evident in the Miami game and he does have the change of direction and short area quickness to make some plays in space. Biggest drawback on Tuggle now is he has no pass rushing skill in terms of hand-to-hand combat or setting up blockers. He doesn't shoot his hands when he engages blockers. Plus, he doesn't demonstrate upper body pop when he does engage. Scouts will love his movement ability, length, athleticism, range, pedigree, etc. but to get drafted he'll need to demonstrate at some point during this season that he is capable of developing moves with his hands as weapons and the upper body strength to pop blockers and seperate.