Lallana is the central midfielder.
I'd argue RB can wait or is at least down the list of priorities.
We don't need another CB - unless we sell one.
We also arguably don't need a striker - what we need is an attacking midfielder who will operate on the left side.
We do need a left back though.
I think we need a RB and a LB; Flanagan is good enough but I don't think Glen Johnson is up to the demands of the full back role with our approach to games. I'm not sure we don't need a striker, especially if we're persevering with 2 up top; beyond Suarez and Sturridge there's not much depth there, unless we're counting on Borini (I don't really rate him) or there's some young player I don't know about ready to make the step up. I think we'll go for two full backs, a couple of midfielders, a wide attacker and a forward.