Not sure why you mentioned McDavid in Hart contention.
Stamkos is easily the Hart favorite right now with Kucharov right behind. They might spilt the votes since they both play for Tampa, but in that case Johnny Hockey would win it as of right now.
Hall still deserves consideration though.
I think McDavid will be in Hart contention if he scores 100 points, which he's on pace for right now, but I don't think he's gonna win it with the state of the team. The only reason that he'd be in contention is because nobody really scores 100 points anymore. Crosby hasn't done it since 13-14 and 09-10 was the last time he did it before that, he was injured for huge portions of the season's in between that and there was also the lockout season in between. I'd have to go back and look at previous Hart winners and see the last one to win it when their team missed the playoffs. I think Bobrovsky in 2013 was the only time a goalie won a Vezina on a non-playoff team. I'd say it was a long time ago that a Hart winner's team missed the playoffs in the year they won it.
I'm looking at the top 10 in points right now, Hall is in a 4 way tie for 10th. I'm gonna say that it's the 3 you mentioned, who would definitely be leading right now. Some of the other guys in the top 10 right now, are guys that I just either don't see winning it, or just not finishing in the top 5-10 in points when the year ends. I don't think Jaden Schwartz will be a serious contender by year's end. We know how the league feels about Kessel, I don't think he's gonna be a serious contender for it. I don't think Brayden Schenn is gonna score as much as he's on pace for right now. McDavid's team sucks, Voracek's team isn't looking good right now. Tavares is a contender for it, Josh Bailey is not. I think Tarasenko certainly could be, much more than his two teammates who have currently outscored him. Those are the only guys who have outscored Hall this season. There's really no goalie's who are a Hart contender, unless Bobrovsky sustains a .936 for an entire season. If he's got those numbers after 65-70 games, maybe he finishes top 3 in votes.
Just looking back on it, no way McDavid gets it. Maybe a top 3 vote with 100 points again, but I can't find the last time a Hart winner's team missed the playoffs the year they won the Hart.