We have some tough choices.
Personally, I'd be fine letting Weddle and Matthews go if the savings meant we could resign Fowler or Littleton. Our LB corps is nothing really special so far, unless some depth player really catches fire, so I'd hate to lose both Fowler and Littleton. I'd like to keep Fowler most, maybe pair him with Patrick/ or another reliable edge. We need a big run stuffing LB, then, and hopefully Ebu, Young, or Howard can be good depth and/or replace Littleton.
Brockers and NRC can be replaced, especially if we could trade NRC for a 4th.
GZ had a down year, but you don't want to be the Bears or in a similar situation where kickers are continually costing you games.
Whitworth has slipped, granted, but I wouldn't mind him back for one last run. I can't think of anyone else on the roster right now that would be a better option for protecting Goff's blindside. Noteboom was untested there even before the knee injury, and I'm not sure Evans or Edwards is the answer there. If he could do one more season, at least until the rest of the line is sorted out (we need a center and maybe another guard, assuming Hav or Evans can handle RT duties), that might be a nice approach.
I could see Thomas leaving, probably Blythe unless we could resign him for cheap OL depth, and I'm iffy on Christian though he might be needed depth if Weddle leaves. I'm not sure Natson isn't expendable as well.
We need to do whatever it takes to find a way to improve both lines and maybe the middle of the LBs. That and some coaching changes/additions (I could see Wade leaving and I would love to see McVay take on an OC or someone in a similar role) might just make for a great 2020. Of course, a rejuvenated Gurley and a more consistent Goff would do wonders, too, but fixing the O line would do wonders for both.
Still smarts that we're the only winning team watching the playoffs, but I feel optimistic about the future. Lots of years that couldn't be said about this team.