I believe they were looking only at plants native to California, and from a quick search it appears at White Sapote's and Guava's closest native populations are in eastern Mexico. I don't necessarily agree with being this strict in the requirements, but I think it's within the realm of being legitimate–although I'm not sure how "native" Apple, Pears etc. are to California.

I've also read that to some degree they were recreating a specific landscape that Steve Jobs grew fond of when growing up. That doesn't really help anybody alive today, but if I were involved in the decisions, I wouldn't interfere with his wishes unless unavoidable.