Are you aware of the NPB league file from last year? Link is below...it might save you a lot of work if you based it from that. Obviously 2007 history should be added, as well as revamped ratings, but it has LOTS of the work done already.
NPB (Japan) Full Roster Set, Version 1.0
As for minor league stats, I have quite a few stats from 05-06 (to do the ratings for minor leaguers in the league file from last year), and some from 99-04. I haven't tried collecting minor league stats for 07, but I may be able to find them.