Hey no one be dissing my gal Kazooie okay
Also a lot of people call the duo B-K when they refer to them, which I feel is more apt because they're both on equal ground (both protagonists of their franchise, not one over the other). A lot of people refer to Banjo singularly, true, but it's likely for ease of saying it. I'd more recommend B-K because my semantic Rareware-loving ass is over here like, "Kazooie exists, too!" The character is not called 'Banjo' in this game or any of their games. They are Banjo & Kazooie. Equal ground. Kazooie counts as female representation.
Also, by the logic of saying, "Kazooie doesn't count because people only talk about Banjo and not her, invalidating her," you're kinda... also invalidating Kazooie, too, by saying this discounts her? Don't just follow the horde. Count her in. Show that she can be a representative of female inclusion in the series (because she is and she is an entire half of the whole character). What is she, chopped liver?
I also just... As a woman myself, a cis woman at that, I don't get why people are splitting hairs so much over female representation in Smash. Sure, I'd love to see more of it, but I'm not going to be heartbroken and upset about it and cry about diversity. I sincerely doubt Nintendo is looking at potential newcomers for their sex or gender here. That's awfully shallow, innit? Whoever we get, we get them because of potential and legacy, not because of their pronouns or what they have between their legs. Would no female characters be pretty lame? Eh, yeah, it kinda would be, but... seriously?
Gotta be honest here: when it comes to representation and diversity in terms of this stuff in Smash, people gotta chillax.