1.) Heroes vs. Villains entirely overlaps with a villain only tourney so it’d be redundant to a degree.
2.) I personally don’t think there’s much of a reason to care about tourney themes in speculation considering Sakurai can just BS whatever he wants after the fact. For example, nobody would’ve batted an eye if Min Min’s tourney was for characters with long reach or if Sephiroth’s was for fighters with wings. There’s way too much wiggle room a character can have with their tourney theme for it to matter at all.
Perhaps
For me Personally, When it comes to Theory Crafting around the online tourneys, The most important thing to look for is for what Type of Tourney is not in the game at all
This is part of why I Expect another Character that originated in the 2010's. We've gotten all the other Era tourneys but this one, and After Steve would have been the perfect time if he was the last 2010's Character (Steve is based of his 2011 Java Release).
Here's a List of Potential Tourneys that Haven't been in the game yet, that could be used in the Theorycraft (with potential characters in the Parathesis)
-2010's Tourney (Monokuma, Velvet, Freddy Fazbear, Apex Legends charcater, Xenoblade character, Dragalia Lost Character, Granblue Character, Fortnite, Etc)
-Swordfighter Tourney (Lloyd, Yuri, Dante, Nightmare, Sakura, Adol, Rean, Rex, Elma, etc)
-Super Bash Sisters (Chun-Li, Velvet, Shantae, KOS-MOS, Reimu, Arhi, Etc)
-Projectile Based Tourney (Reimu, KOS-MOS, any FPS/Shooter Character)
-Villains/Rivals only Tourney (but like you said, it could be considered redundent) (Eggman, Monokuma, Shadow, etc)
There's probably more, but these are the main ones
I think the 2010's Tourney is the most important one to look at. The Projectile based tourney could be kinda considered redundent since like
pupNapoleon
mentioned back then, Steve's Tourney includes alot of Characters that are based around Projectiles. The Swordfighter Tourney and Super Bash Sisters tourney are ones that seem logical to have, but unlike the 2010's Tourney, we don't 100% know they will do a tourney like that
There's also the problem that they can just Throw these tourneys at any time. But until the tourney shows up, the Theorycraft continues on