I went through the same research last year. I found these 2 links VERY helpful.
1) Attendance Areas. If you are interested in Mission San Jose High School, note that Weibel students will go to Irvington High School; not MSJ HS.
2) Fremont Unified provide historical overflow charts containing all school and grade. Be aware that historical data does not guarantee future behavior. (Especially with current budget issues...) I would recommend you contact the specific school directly.