Well looking into it
With Plant, we got all 5 Characters in FP1 released in the Span of the year, and we also got Plant released. So that's 6 Characters released in only a Span of a year
However with FP2, we only got around 3-4 Fighters this time, 4 if you want to start with Byleth. So I would say that Production has slowed down. though the Pandemic did throw a Wrench into things, but I think even without the pandemic, we would have gotten the same amount of Fighters
I do think that if might still be in groups of 3, it's just that there are less people in total in each group.
Now with that being said, If this group thing is still a thing, I don't know what happens once the people who worked on Min-Min finish CP9. I guess it's either they go ahead and help finish production on CP10 or CP11, or perhaps they are just let go.
The other thing I have to say is that I characters require different processes, Including Animation, Modeling, Renders, Composition, Stages, Programming, Balancing, Voice Acting, And Different people specalize in each
Like the people that Animated Min-Min, Once they finish animating so people can program her in, I don't think they just stop there and go take a Break, I assume they get to work with whoever FP9 is, so in that case the process should be faster. As they get close to completion, I Imagine it might get faster to complete the characters since there isn't as much stuff they got to do, or Characters to work on. that or people exit the development team, which goes well with Nintendo since they could stop paying those people, but yes