Quinn Duffy states in the tweet that they, as in Relic, doesn't own "the game anymore" so best guess is that SEGA does indeed.
However that leaves the question why they had those polls and stuff last year asking for feedback on a possible 3rd game when they don't "own the game anymore" and if so who is gonna develop it then, Creative Assembly? They did stir off from Total War with Halo Wars 2 so it's a major possibility.
I like that you come back to the survey. Its a strong indication that CoH3 is planned. Creative Assembly is bigger than ever and would certainly have the manpower to produce the game.
I for my part would prefer to see a CoH3 developed by Relic.
The work of the mod team and the feedback of he community have shown the huge potential of community input. Relic should come back to the community (at least the mod team) - there are huge chances for both sides here!