Tarasenko would be an A+ return because he'd be under contract for four more years and we wouldn't have to honor his NTC.
We also probably get a better return in terms of futures for Tarasenko than we would for a trade of Stone with an extension worked in because Tarasenko would have no say over where he'd go, where as Stone could block a trade or depress the market by limiting the number of teams he'd sign with.
That will never happen though. I think Stone is way too close to UFA status to do a trade with an extension baked in. Expect basically the Brassard or Nash return from last year's trade deadline with maybe a few extra pieces.
From a team like VAN, maybe something like Virtanen, a 1st, a 3rd, a B prospect and then a conditional 2nd/1st based on similar conditions to the Karlsson deal.