I agree with you. With Shields and Wilson it's fine if they came back at veteran minimums but I would think Kiser could take Wilson's role as the main ILB backup and I would prefer to draft a CB in the top 1-3 rounds that could be their CB4 this year with an eye on replacing Talib in 2020.
With Mannion I think they need to get a veteran QB with some experience. Mannion has thrown 53 passes in 4 years with 2/3 of those in that one start vs. SF. Backup QBs are what they are but I would rather have a Colt McCoy, Ryan Fitzpatrick type. I highly doubt Goff is learning anything from Mannion.