For simply making the Seahawks team better (for longer than 1 season) and not doing extensive research on the players for scheme fit the list comes down to.
Cards: Fitz, Peterson, Washington, Campbell
49ers: VD, Willis, Iupati
Rams: Long, Jenkins, Quinn, Brockers, Laurinaitis
I have a feeling Justin Smith and Willis are huge parts of what make Aldon and Bowman great so I will pass on them for this. I would want Justin the most but he's too old and banged up.
Cards: It seems impossible to not take Fitz here but I'm going with Patrick Peterson. He will replace and upgrade both Browner and Leon. This would complete our elite secondary.
49ers: I really wanna take Vernon Davis here but I think upgrading OG is more important for the offense so give me Iupati. (LB would be easiest to upgrade in draft).
Rams: Quinn could possibily be a product of Long on the other side so it's between Long and Brockers for me. DT is our biggest need but Long is proven. Going with Long.