Well, with Bill & Ted 3 potentially being pushed back or going to VOD, it could actually serve as good synergy now whereas before it would've come too late to help the movie in any way.
I still highly doubt there's anything to this though. With the theater having to be socially distanced, it would really limit the amount of people who could see it and demand would be high. Although if i'm Universal and i'm seeing many fans are skeptical about coming to a highly changed HHN this year, adding in Bill & Ted last minute for the purpose of getting certain people of the hump to want to come to the event wouldn't be a terrible idea.