Let me try and answer your questions to the best of my ability
1. If you home falls under a particular school district the school district must accomdate your child. School districts can handle enrollement as they please. San Francisco for instance has a diversity program so they will send children to schools across town even thought they may live right next to a school.
In most cases school districts have school boundries within the school district area, as is the case for schools in Santa Clara Valley. The school district usually does not guarantee a particular school even though a student may live within that school's home boundries. The district may send that student to a different school due to over crowding. If you live in the district however, the district must accomodate you at one of their schools.
2. I'm not sure about applying, but you must enroll your children in the school. Some schools require the parents to enroll their children every year, and provide proof of residency within the approved boundries every quarter.
3. Most school districts have an open enrollment policy. That means if you live in the district you can have your child go to any school provided their is space for your child at that school, and children who live in that school's boundries get priority over children who live out side. Santa Clara has an open school district. It also has two open schools Milikin and Washington. These require a lottery system and application/qualification process.
4. Not sure what your asking here, but if you need any more clarification feel free to contact me.
As for websites you may want to try the individual websites for the school districts you are considering. If you are interested in test scores and demographic info you can stop by my website where there are links to state information about schools and school districts.... more