Which LB is droppable?

Scoring:  2 pts/tackle, 1 pt/assist, 2 pts/TFL, 3 pts/sack, 3 pts/fumble recovery, 6 pts/int, 1 pt/pass defensed or force fumble.  DL's get an 6 pts/sack

DYNASTY League
Start:  2 DL, 3 LB, 2 DB

DL's:  Charles Johnson, Ninkovich, Morgan, Hunter
DB's:  Berry, Barron, Harper
LB's:  Laurinaitis, Mayo, Loften, Demario Davis, Dent, Erin Henderson, Roach, Daryl Smith, Sio Moore

I drafted Sio Moore this year and Demario Davis last year...as long term investments in dynasty league.  I'm still hoping Davis develops into the hyped LB2 w/LB1 potential I read about all summer.

Laurinaitis and Mayo are weekly starters and Loften had been my "safe" LB3 in the past...though he's been disappointing early.

I drafted or picked-up via the waiver wire: Dent, Henderson, Roach, & Smith hoping that one or two of them would become solid LB3's w/LB2 potential...possibly weekly starters.

Looking at the 9 LB's on my roster, which would you consider dropping to open up a roster spot?

I'd like to pick up a fourth DB...like Aaron Williams or Mundy....or a young WR with potential...like Quick or Ace Sanders.  

There are a couple of other LB's sitting out there too...Levy, Trevathan, Weatherspoon (injured), or his replacement Bartu.  Are any of them better options?

As you can tell...I'm have a little mid-week boredom and am tinkering with my team.

I really appreciate the input.

I think I would stay put. I typically only roll with one backup DB in most leagues.