Enrolling in Kensington or Madera AFTER Kindergarten

We currently live in Berkeley but are considering buying a home in El Cerrito, targeting homes zoned for Madera or Kensington Elementary. Our oldest child will start Kindergarten in the Fall, and is already enrolled in a Berkeley elementary school. We have missed the open enrollment period for the El Cerrito schools, and would realistically not be starting there until first grade. I was told by the WCCUSD transfer office that some families who start after Kindergarten are NOT assigned to Madera and Kensington due to high demand, even if they live within the zones for these schools. She did however, tell me that this is usually only for families that miss the open enrollment period ... but it made me nervous. I'd hate to buy in a specific school zone and then not get a space in that school!

As a related question, it would also be helpful to hear from any families that have had inter-district transfers granted by BUSD, in the event when a sibling already attends the school but the family has moved. I was told by BUSD that these requests are not typically granted, and honestly would prefer to have my kids in our home district if we move anyway. 

I would love to hear from any families that enrolled (or tried to enroll) in Madera or Kensington post-Kindergarten. Any advice is helpful!