Well, Ino is using the flower bomb, since we've actually only seen her use the mind-transfer jutsu.. (And using it like a baws!)..
But my guess is, that they thought she needed an attack that wasn't based on mind-transfer, and since she works in the flower store, and that was kinda her thing they added a flower based attack.
Now, regarding the huge-ass ball Tenten got, this was shown in the Anime. And while it is true this wasn't in the Manga, the games are shown to follow the Anime and not the manga. Thats why the gameplay doesn't include anything that isn't shown in the Anime, at the release date - And this is likely because they don't want to spoil anything for any fans.