I guess I just don't understand most of this thread.
If you've read in several novels that Saavik is half-Romulan, then by all means, believe for yourself that she is half-Romulan. Just accept that a lot of fans have never picked up a Star Trek novel and the same is not true for them. What does it matter if it is "official" or not?
The only Trek book I've ever read is the Star Charts. I refer to it from time to time to figure out where one planet or whatever is in relation to another. I couldn't give a flying fig whether or not it is "canon." It's real enough to me.