My Illogical Theory
Despite Tierno's moroniness I have made a theory. Hooray! :D
Well, Tierno does dream of making a Pokemon dance team - this may be why he doesn't have many moves. Those may just be the only moves he taught his Pokemon, because they were suitable dance-moves.
And pay attention to the movesets they have. Roserade has Petal Dance, Crawdaunt has Swords Dance, and Talonflame not only has Swords Dance, but Acrobatics! Acrobatics seems like a pretty kinaesthetically-pleasing move. :P Of course, the Pokemon may have got the less dancey moves to create a minor challenge. Remember, Tierno does state that he isn't that good of a trainer, and only having less than four moves on a Pokemon is pretty not-that-good-of-a-trainer-ish.
But of course, like Fizz said, the game is quite hard to hack at the moment and correct information is very hard to extract from the game, so there may be more moves that Tierno's Pokemon have.
All in all, Game Freak is the one to answer your question correctly, but for now this should be a suitable answer.
Though, in Tierno's defense (xD), Tierno's Battle Maison team is two Pokemon with full movesets. So yeah. :3
Hope I helped. :)
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