In terms of Direct predictions, I'm not sure we'll get any last minute announcements, especially since every character will be revealed before the game launches, presumably to get ahead of any potential leaks to avoid what happened last time. My guess:
September Nintendo Direct: I think this would be a major first party character announcement, probably no echoes. My guess is Bandana Waddle Dee or Skull Kid. If there are echoes, which I'm not sure where else the rest would fit, this is where I'd see Dixie Kong and Isabelle.
October Pokemon Direct: I don't think Smash would be featured in the Direct itself, but I think around this time we could get an announcement of the Pokemon rep (if there is one, which I don't consider a lock). My guess is Incineroar.
October Surprise: I think at some point we would get a surprise reveal of a popular lesser known character. My guess would probably be Isaac, with Felix as an echo. If a Bandai Namco character is actually in, then this is around the time I think they'd announce it instead (and in that case, my guess is Lloyd).
November Smash Direct: Similar Direct to the August Direct. I think a major third party character reveal would begin it along with a stage and music, with a fan favorite to end it (My guess is Banjo & Kazooie to begin, Geno to end). Third party echoes, my guesses are Shadow and Ken. Online, a few brand new stages, Minecraft stage with Creeper assist, assists/pokemon, single player mode (NOT called Spirits). Third party echoes including Shadow and Ken would be revealed.
I do hope, though, that we get more characters, and more Directs. But being conservative, I think this is how they would spread it out.