The tie-ins from the 1980s contradict each other (since it's not a shared world the way Star Wars tie-ins are a shared world with shared continuity), so it's more than you can pick and choose. So, for example, while I choose to consider Vulcan's Glory by Dorothy Fontana as part of my personal canon, if parts of it don't agree with Diane Duane's Spock's World I may prioritise.

For example, Spock being the first Vulcan in an integrated Starfleet crew was widely held fanon until T'Pol made it Officially Not Canon via retroactive continuity. Also, Vulcan's Glory has other Vulcan officers aboard Enterprise. The plot requires it. So it all depends on what you want. I cherry pick fanon from the novels/comics/websites/non-fic tie ins, and keep what I want and ditch what I don't on a per story basis.