If you read the tea leaves, the league and the players seem willing to let things roll into next year. I suspect if the season were cancelled the CBA and all contracts would just all be pushed up a year.
I would think that would mean the period to negotiate and/or rescind a tag would reset as well. If true and the Giants were faced with the question of tagging Williams again, now a year older, do you think they would do it again? Maybe faced with uncertainty both sides would be more motivated to sign a multi-year deal?
In your situation, I'd assume they'd just tag him again. Whether contracts get pushed back or stay the same the value won't increase that much. The bigger issue is the salary cap next year. Until we know what that is and how this all plays out there is just all speculation. Williams may be more inclined to sign a long term deal. However, maybe the Giants are less inclined because of the salary cap.
If the tags remain the same and the cap goes down, effectively making Williams more expensive as a percentage to resources I can see them not tagging him.
Williams tagged at age 27, with the hopes of extending for big guaranteed money at 28, 29, and 30 also starts to come into play. My guess is they’d let him walk.
Who knows, if he hits the market next year he may decide, in the end, to resign with the Giants anyway since he's unlikely to receive his asking price from anyone besides DG... And next year his market value might well shrink.
How different is his age from Tomlinson's? Not much IIRC. I doubt his age is a factor.