Haha. I really enjoy lurking around here, and I haven't see such wonderful excitement and passion in a while. Since you really want to know some new info.... here's my suggestion. Execute the beta file and translate the codes. The codes can reveal many details. It may or may not contain information about the last four new characters. Remember, the game haven't gone gold yet.
I am no expert at this technique, but I know one person who can: Fadi002. Originated from Naughty Dog forums, he's a tech genius who used to leak many new info about the upcoming new Uncharted MP patch by executing the patch file. You can ask him for information on how to do it and try it. I don't know if he has the beta file to execute though.