Mouser, he says "they look like they may contain information relevent to the stream ogg files", I take it therefore that there are actually ogg files. It seems like OrangeC has already ripped this game, and he says to use ww2ogg.
The bnk files are sound banks, we've seen them before but not really done anything interesting with them. They usually contain RIFFs embedded within, and you can extract them with any tool (like vgmtoolbox) that can rip RIFFs.