I think Maybin and Brown might fall well past #11. If I am the Bills I wait on DE until #28.
From the end of the 1st through mid 2nd I'd watch for: Michael Johnson, Larry English, Lawrence Sidbury, and Connor Barwin.
If defense is the pick at #11 I'd seriously consider Clay Matthews Jr.; we need help at OLB and Cushing, Lauriniatis, and Maualuga are all ILB's.