If there are co inventors and one inventor files for and then receives a patent, under the new AIA laws can the co inventor invalidate the patent, or get his name on the patent that issued? It seems to me that first to file means nothing if ALL true inventors must still be named.
I do not see how this relates to first-to-file at all.
All inventors need to be named but if they are not named or if the named inventors includes people who should not have been listed, the patent can be fixed later as long as everybody in question signs off on what the correct inventorship should have been. Pre-AIA it was possible to end up with an invalid patent even if all true inventors and incorrectly included non-inventors agreed on the proper inventorship later. Pre-AIA there was a requirement that "no deceptive intent" was involved in the original filing. Now that has been eliminated.
Pre-AIA if X filed as sole inventor (with deceptive intent) and later Y and Z caught up to him and asserted their co-inventorship, even if X was persuaded to fix it, legally, he couldn't (due to his original deceptive intent) and all three were screwed because it was wrong and couldn't be fixed. Now it can be fixed without worrying about orignal deceptiveness.
This is from the USPTO AIA FAQ: