I've already said before that I really don't like Williams' value at 16. He can pass rush but I don't think he can be much more than a pass rush specialist at the next level, just what I get from watching him. I don't want to get into it, but I can't see him as BPA over Corey Davis, Cam Robinson, or a couple of the other guys you've got on the board. I'd honestly take Watt over him - and I don't want Watt at 16 either - I think a trade back would be a much better decision if the board falls the way you've got it.
Early in the process I really, really didn't like Smith-Schuster, but I started to change that opinion about a month ago. He's not the fastest guy on the planet, but speed isn't really the main thing we're looking for, and it's secondary to the fact that he gets open in the short field anyway. He would be a good Aiken replacement for when we need a reliable target within 20 yards. I like the value here.
Magnuson in the mid 3rd is probably my least favorite pick here. Just from what I've seen of him: lack of strength is a red flag, his footwork can get real sloppy against speed rushers (just throw on the Ohio State tape and you'll see what I'm talking about, his kick out wasn't fast enough to catch his man often), and I don't really agree with your comment about pass protection, I think he's pretty weak in the department. Honestly when I watch him I only see a swing tackle ceiling, I don't see a guy that can step in at RT any time soon in the NFL.
I watched Walker forever ago, so I will have to go back and watch him to give analysis, but I do remember that I liked him less that other options that'll likely be available at his position, most notable Jarron Jones (whom I think can be extremely good with some coaching up, the way he dominated Miami's oline showed me a lot, obviously isn't ready to go day one, but if developed right I see a very good player here) and Nazair Jones.
I love Perine (though I hate how his name is pronounced, I'm going to keep saying per-een and I'm not stopping), great power and his balance is unreal. However his knee issues do give me some pause. Power guys with knee issues is a legitimate red flag.
As an overall note - I can't see us passing totally on the strongest CB class in forever. There will be great options at our second and third that may be starting quality players immediately that I think have to be BPA. Carr is only a one, maybe two at most, year fix at #2 CB, and even with him we know Jimmy will go down at some point again putting us in a terrible position since we are still severely lacking in depth on the outside. Canady is an interesting developmental guy, but I think it'd be foolish to put our depth trust in him after only one year of development.