As a crude approximation, a crystal oscillator is crystal, with a phase-locked loop wrapped around it. Which, doesn't appear in 217F, so use the default model for an electronic filter.
I'm puzzled as to the detail involved. Usually, an oscillator is such a tiny part of a board that its actual failure rate is irrelevant. As a general rule, the component count approach to 217 is extremely conservative, and few people do the analysis that way.
TTFN