I agree that those are all needs. But there is also FA.
I would like to go after Karlos Dansby in FA and a veteran wideout. If Dansby is too expensive, I'd go after a veteran pass rusher like Shawne Merriman (if he is a UFA, which is unclear right now, depending on the CBA status and on what SD does with him). Either way, I'd like to fill a few needs prior to the draft.
If we have a veteran ILB like Dansby via FA, then I go for 2 pass rushers in the draft - ideally, a strong side guy like Dunlap and a weak side guy like Austen Lane, Jerry Hughes, Sergio Kindle or Ricky Sapp.
If we have a pass rusher like Merriman via FA, then I try to trade up for McClain if at all possible. Brandon Spikes and Eric Norwood are backup options, but I'd go after McClain as long as he doesn't go top 10.
Add a guard via the draft and some depth at RB, and possibly a development 3-4 DE, and we would be in fairly decent shape in terms of personnel.