It’s taken me a long, long time to write (thanks in part to how ridiculously complex some of Dream Team’s many bosses are), but our official boss guide for the game is now available. You can find it at the following address:
It’s not 100% perfect (the pictures are what I could find on Mario Wiki and the stats are merely what’s available online at the moment), but there is a unique strategy given for every single boss opponent in the game, as well as information on how to dodge every single one of their attacks. There’s also information about the giant bosses too.
So yes. If you’re having trouble with the game even now, I’d definitely advise you check it out!