Japanese writing is actually very easy and quick to learn. And even without it, you really only need it in KH2. There are already plenty of game transcripts to fill in the text only cutscenes, as well as some translations for new scenes. Since there's english voice acting, that's the most you'll need it for KH1.
I guarantee by the end, you'll at least identify the potions and ethers in the menu.
and Swap Magic is infinitely easier than modding a PS2. the most you have to do is replace the skin cover on the system.
At the most, I'll probably end up printing copies of the menu screen for reference. So tacky xD
Thanks for the advice, everyone!