Yeah, I finally found a walkthrough for each of the girls in one of the links on the address you gave me. I don't know if every step is critically accurate though, since it seems very specific about talking to Will and Airi at set times early on (which shouldn't directly influence the later characters). It's gonna be a bumpy ride with my knowledge of Japanese, but I'm way better off now than I was. Thanks!
*Edit*
The good thing about the guide is that it's very easy to use, plenty of spacing and good format makes it easy to read. The bad part about that is that it takes about 18-20 pages to print the path for just 1 girl... -_-;
Have to print it because the game becomes very unstable when you multi-task. I hope I have enough paper...