I say Graham and Welker for sure. I think I would take a hard look at Mathews for a 6th rounder. That's a great value, I still think he will finish as a top 10 RB. You'll still get your first rounder, and if all those guys are there when you pick, you either recoup Forte or you get someone who is comparable in DMC, CJ or Richardson.
Tough here, why? B/c Ryan broke his collarbone and is questionable for SOS but that being said, he still is worth the risk of a 6th round pick. Your selections: Forte, Matthews, Welker. If Graham is good value I could see tossing out Matthews for Graham.
You have a great 5 to chose from, to me I"m keeping Forte, Welker and Graham. Unless you know for sure all those players are there for you in rd 1 I'm not taking the chance. I don't trust Matthews to stay healthy and Vick I"m keeping only if you can get a quality backup with his injury history. GOod luck.