Ki Blast Cannon = Tribeam, they changed the name (in Budokai) because Tribeam wasn't actually a beam, and Neo Ki Blast Cannon is still the same attack with continual shots.
I don't mind Kamehameha being learned via Third Eye instead of a given attack, in fact it would make more sense that way, but in ESF the transformations also represent points in the show (such as SSJ Vegeta magically learning BBA and FF) and Tien had mastered the Kamehameha after you see him meditating, so it works in that way too. I'm not particularly bothered as Tien has lots of cool attacks to keep him apart from the other characters, but if he had to learn Kamehameha, he would not have any steerable beams.