Definitely not Scherff. If all 3 are gone which I highly doubt but if they are I'd take one of the pass rushers, not sure which one yet
Scherff is NOT worth a top 6 pick at all. Guards should never be taken that high, and he is not a future LT IMO. I would take an offensive line player if one were worthy of a top 6 pick, but at this point the only picks worth it at that pick will be pass rushers (or the 3 that you mentioned).
Depends on how the o-line starts to grade out. If a complete future LT stud is sitting there we take it. If there is no o-line man worth the pick we try to trade down or take the best pass rusher available. maybe Gregory or Ray.