I looked it up, and you're right, looks like you can use either "for" or "of," sorry! It may be a British vs American English thing. It'll also depend somewhat on the exact nature of the sentence...i.e. "The expectations for Jane" versus "Their expectations of Jane," in the latter version, because it's "Their expectations," it sounds mord natural to me to use "of." As an American, I would say: 'The expectations for Jane are high, but they are nothing compared to what people expect of Tom.' The reason why I used 'for Jane' and 'of Tom' is that the second part of the sentence relating to Tom: "to what people expect of Tom," to my ear, the "to what" part sounds more natural with 'of.' Your other versions sound good to me (except if 'expectations' are in plural, use 'are). "Their expectations for Jane are high. Their expectations for Tom are higher than those for Jane. " "Their expectations for Jane ARE nothing compared to what they have for Tom?"

Close, the second part is good. We would say: "The expectations FOR Jane ARE high." Expectations is plural, so it would be " are" instead of "is." From the context, the 'expectations' are external to Jane, i.e. imposed by the organization, by her boss, etc...so we would said they are for Jane. If you were to talk of Jane's expectations for herself, a project, etc., you would say "Jane's expectations are high."