personally, with only 3 limpers and me with AKo LP, it's very hard for me NOT to knock out the blinds with a raise...

with 4+ limpers it gets tricky

I think you're right about the SB, but the BB should call the raise with almost any two cards. If one person has raised (2 bets), and 3 people have limped whom you expect to call the raise (another 6 bets), the BB is getting 8:1 to call the late position raise. At most, the BB is a 4:1 dog at this point, and so a call is definitely correct before the flop.