Chase Allen is going to have a tough time making the roster because Rey Maualuga was signed to give us exactly what Allen is best at, and Maualuga is Burke's safety blanket so he's got the advantage.
Allen is big and strong and plays like a big and strong guy. He does not always play like a guy that can time fairly well in a 40 yard dash, etc. In fact, against the Ravens, he was sluggish as HELL and looked like a 5.0+ player. He had a truly awful game against the Ravens, but he had better days against the Falcons and certainly the Eagles. The latter was in part because the DL kept him clean and funneled things to him pretty well.
Deon Lacey is the guy that is safe that people don't realize is safe. Standout special teams player, shows instincts and range in coverage that are not common. Has been surprisingly physical when it comes to sticking his nose into the blocking scheme, getting off the block. His weakness even in the CFL was inconsistent angling toward ball carriers, which can lead to awkward and botched tackle attempts. But there's too much good in there, so he's going to be on the roster playing special teams and possibly being trained to be a nickel specialist, until he cleans up some of his weaknesses or they find a way to hide them.
Personally I see five guys at the LB position worth rostering (if you exclude Neville Hewitt who is ailing), and that's a problem.