Oh, nevermind. But also, this adds a third distinction to the list.
In the case where it's a Party (not a Solo adventurer), there is the question of the number of protagonists : is it a Single Protagonist with sidekicks (e.g. the company of adventurers is "Gorion's Ward and companions"), or is it a Party Of Equals (e.g. "The Avengers") ?
I have my preference for Party-based RPG, Single-Player, and ... I'd say my preference for the number of protagonists, at least what I'd wish to find in BG3 given how the game was advertised, but I have no idea what Larian is actually planning to go for on this, and that would also be going off-topic a bit too much. Since the topic was on the number of adventurers and how the game fails are delivering on the Party aspect.
@Kappa Omicron : thanks.