In the end it all comes down to Lucas. The FO has made it clear that their plans for next season include Peppers and all other starters are back. Thus any free agent moves will be for backups.
With Hangman probably leaving and Vincent being oft injured and a FA after this season, it wouldn't surprise me if OG/C is now the second biggest current need for this team behind another DT.
DE and CB needs are all contingent on Lucas and Peps future.
Vincent did have a history of groin injuries but he was the only one that didn't get hurt and miss games until the very end of the season this year. If he fully recovers he should be fine. But we could definitely use some back-ups.