I have no idea what those files are, though I can make a guess:
Since the CPK is over.cpk, and the files contain strings like adhoc_lobby.ovl and game.ovl, they are probably chunks of executable code, aka overlays. The code is little endian MIPS so I assume this is from PSP. I'm guessing the MWo3 header stands for Metrowerks overlay (3?).
Beyond that I don't know what you expect to do with this, it is code, not data.
Because I want to edit the data inside this file. If you have time, just try to use DKZ Studio to open it because the previous afs file (not cpk file) can use DKZ to open it.