Those 6 WR seem pretty safe to me. It seems like a complimentary bunch; a nice mix of speed (Givens, Austin), size (Quick, Britt, Pettis), possession (Bailey, Pettis).
But; if Moe has a nice preseason I could see him nab Bailey's spot during the suspension and that might be enough of an opening to threaten Givens or to a lesser extent Pettis come week 5.