Before we get our hopes up (again) maybe we should think rationally (again) about what's been announced thus far.
We have five new character slots confirmed. No confirmation of multiple waves. At the price of DLC packs now, I don't see them doing much more than this; at least not for a long time.
Keeping in mind that Sakurai will be spreading these out across a year and using them to keep hype for the game, here's the spread out I'm predicting:
1. Geno. Unfortunately I don't see Sora due to licensing complications with Disney (looking into it, turns out Disney is the ones with rights to the Kingdom Hearts characters!), but Geno is an obvious inclusion. I think he'd be a great way to ease us into the first paid DLC passed the plant boi. It's a good sign that there's been no signs of the Mii Costume returning. Stage: Rose Town + Forest Maze
2. Skull Kid. Sliding out of the assist trophy room is a big deal for the little guy. Geno and Skull Kid would make a really great (Mario + Zelda) pack for people, and would be an exciting addition to the roster. I don't see people getting mad about this. Stage: Termina Village
3. Jibanyan. It's not exactly thrilling to see out here, but Japan loves this little guy! Luckily he's recognizable enough to appear as DLC since Yokai Watch is actually a decently popular show still, even in the US. It'd also be perfect timing to release around the time Yokai Watch 4 drops. Stage: Springdale
4. Lara Croft. You guys know me as the "Crazy guy who thinks Lara Croft would get into Smash" guy, which is totally fair... but, I still think she has potential to be a surprising guest character with a Nintendo history and an incredibly popular fanbase. Since she'd be dropping around Late 2019, it'd be a good way to reignite the fans around time for the holidays. Stage: The Temple
5. Banjo & Kazooie. The perfect character to send off the first wave of DLC and potentially the last character for Smash Ultimate. The hype of this character is insane, and the love the fans have for them is immeasurable. Making everyone smile is a great way to end of a wild and weird DLC set. Stage: Click-clock Wood (Could do Spiral Mountain!)