Just look at the Japanese official site. Most of the characters share names across regions, save for King Koopa, Murabito, Gekkouka, Rokkuman, and Rosetta & Chiko.
Also, on the subject of the Japanese release, do you think blacking yourself out from most parts of the web would be worth it to prevent spoilers? What if the situation on all characters turns out to be the Sal Romano leak spot on and no more Brawl cuts besides the obvious ones? Hell, word of mouth seems contentious enough for prematurely surprising me.