He is 6'1. Not exactly screaming size.
1. No Davis hasn't
2. Mattews has been better than Holmes. Plus you don't spend a 2nd round pick and give up on the player. Right now: Mattews, Benjamin, Jones are locked. Tate is there for Special Teams. Bills have Thompson, Holmes and can sign Streater. Holmes is expensable.
3. I'd rather see John Miller than Ducasse.
4. FullBacks aren't very important; plus the Bills have one pretending to be a backup RB right now