Ideally I would want a companion per class (so 12ve?). I think I would be satisfied if we got another 5 on top of the 5 we have seen in EA. Anything less would be cutting it close to me, as I am not terribly fond of our confirmed roster. That said with a smaller party size, Larian can get by with a smaller companion roster - 9 companions would give 3 full playthroughs with no companion overlap. And with high reactivity, there is an appeal to mixing up different companion composition to see what interactions might there be.
Non-origins companions being cofirmed also opens some questions:
How many origins/vs non-origin companions will there be. Will we get recruitable party members without companion content (like sidekicks in Deadfire? - I doubt it. Excess seems to be the name of the game for BG3).