As someone who has watched almost every Aggie game in the last 5 seasons...
Joeckel is the slam dunk franchise type LT of the two lineman. Matthews is more of a mauler in the run game than Joeckel, but Joeckel has more skill to handle speed off the edge which is more important in the NFL. Both have a LOT of college experience, having started since they were true freshmen. Joeckel is a top 5 talent, Matthews can go in rd 1 for a team that needs a RT, he will be a good pick.
As for Moore, yes he is GOOD, real good. But he is NOT a Von Miller and will not be a gamechanger on his own. But, with the right pieces around him and the right scheme, he should be a productive NFL player.
Manziel..... I really don't know what to say about him at this point. He just seems to good to be true, but he had games like this all year, and got better over time passing.