who is shujinko, and is he on the main character select screen?

He's the konquest guy that u play as and can change the name afte ru beat conquest but idk if he can or not ??

Shujinko (think that is his name) is the monk you control in Konquest. There should be a spot for him on the main screen.

Are Shujinko and Apep gonna be playable in arcade mode maybe as hidden chars?

The possibility of this character having ALL fatalities must be there, considering he can have ALL fighting and weapons styles.

Personally, I would love to see him have one original fatality that all "Shujinko"s would have that no other character has, while his 2nd fatality would be one you could choose from existing fatalities. That would not only enable him to be different from other characters (his own fatality), but different also from other "shujinko"s other players develop (each player choosing the other fatality themselves).

Wouldn't be cool to beat certain characters while traveling and after you win,they teach you one of their fatalities?

That is a neat idea as well. To unlock other fatalities as you apparantly do stance sets. The more I think about Shujinko, the more curious I am as to how he will work out. Fatality-wise, I haven't a clue. In another post, someone asked if Shujinko, being that you can choose your own fighting styles, will have style branch combos possible. Excellent question.