Something that's worth noting...
"Ippongi Ryuta of Cheer Squad" also shows up on the "List of Characters Sakurai Mentioned In His Blog," which doesn't confirm anything except that Sakurai knows the character exists, which is still nice.
Japanese Poll, Most Requested Characters in JapanThose are the results of a poll held in Japan, some time well before the launch of the Brawl blog. "Ouendan" isn't very high on the list, but the fact that they placed at all tells me that they're likely to show up as an assist trophy.
King Dedede(5)
Diddy Kong(4)
Geno(4)
Ike(4)
Ridley(4)
Captain Olimar & Pikmin(3)
Krystal(3)
Takamaru(3)
Windwaker Link(3)
Animal Crossing MC(2)
Claus(2)
Demiru(2)
Isaac(2)
Jeff(2)
Kawashima(2)
King K.Rool(2)
Lip(2)
Lucas(2)
Mega Man(2)
Oguma(2)
Ouendan(2)
Sukapon(2)
"Ippongi Ryuta of Cheer Squad" also shows up on the "List of Characters Sakurai Mentioned In His Blog," which doesn't confirm anything except that Sakurai knows the character exists, which is still nice.