Terry will be announced tomorrow.
Or maybe next week.
Bwahaha, I was right!
SpongeBob is Fighter #10, and will be revealed next season. Screencap this.
edit: I just received more info:
-SpongeBob's victory theme is a short remix of his themesong.
-There will be remixes of the F.U.N. song, the Campfire Song song, the themesong, Best Day Ever, Plankton's theme, Industrial Park (BFBB), Jellyfish Fields (BFBB), and Ocean Man. There may be more, my source isn't sure.
-Gary, Patrick, and other characters appear in his stage, which is a travel stage that takes the fighters to each area in Bikini Bottom. Characters also appear in his victory screen; just Gary, his friends, and sometimes Plankton. One has him holding a golden spatula.