Here's what I picked out from the first video:
-Corneria seems to have a higher ceiling than in Brawl but be otherwise smaller?
-Diddy's dsmash looks the same as always.
-Tomodachi Life has a very high ceiling unless the FD form is on the roof and that is what was shown.
-Flare Blitz is usable in the air, still straight horizontal.
-Pac-Man's side special seems like it will keep going a bit after running out of the dot trail.
-Did we see the FD forms of N's Castle and Pac-Maze in this? Those stages were confusing when shown.
-Kirby's third inhale variation is a jumping mouth grab, can probably copy.
-Kirby's third Hammer variation is a huge hammer, I can't tell what special about.
-Kirby's second Stone variation is a huge version, I can't tell what's special about the third.
-I'm not even going to guess what those Final Cutter variations are supposed to be...
-Equipment clearly can have a huge impact on character parameters; we saw Kirby running at near-Sonic speed. The total number of choices for equipment types seems really huge too with fairly poor organization.
-Distant Planet has fairly imperceivable differences if any.
-MONOLOTHSOFT was added to the credits at the end.
I feel like this would have been absurdly informative to someone who could read and speak Japanese, but instead, I'm an American who is just looking at the pictures in a book and trying to tell you what the book is about.