You need "immediate help" on something you're not to receive til next month? Any Wii can be softmodded (including Korean, Japanese). No, they're not the same in terms of language. I hope you speak Japanese
Failing that, you could source Any Region Changer (ARC) to say change it to U instead of J. Japanese, like U, is NTSC. Korean Wiis, I'm not sure (NTSC/PAL) but that's irrelevant as you state Japanese.