I also expect to see a lot of the same "types of characters" as we saw in Volume 1 in Fighter's Pass Volume 2. In that I feel like a "huge third party with a legacy", the fan favorite, the first party, the new and somewhat more niche third party, and new and exciting third party all feel like similarly full of potential categories to satisfy lots of Smash fans with another character on top of them. I don't think it'll be an obvious 1-to-1 thing in regards to how Volume 2 will be handled, but I could easily see them going back to similar wells.
I also think that we'll see Sakurai make a couple of additional never-evers happen. And no I'm not necessarily referring to the characters people label as such, but rather the types of character you never expected to actually get into Smash happening in a big way like Joker, Hero, and Banjo & Kazooie were all for this specific cycle. They were all three to some degree impossible picks (Dragon Quest being such a complicated IP that Square Enix is protective of still should definitely earn Sakurai more credit than he gets for its inclusion) that even if they weren't all the biggest fighters, really brought some incredible dreams to reality.
It's kind of weird, Terry and Byleth are the only two of the Fighter's Pass that seemed more realistic as picks considering what they were, and even Terry is a big maybe considering SNK's relative place in the industry.