Hi
@laurela.
1. Absolutely yes.
2. I don't see any reason why they'd have to keep it. But I like the feeling of keeping my kids school-smart too.
3. Non-heirs can go to boarding school.
4. Yes, you can age up upon completing requirements. But only then (and aging up naturally without fulfilling requirements is Game Over)
5. Only if the opportunity fills the Career, Skill, or Special Op slot. Some university ops do (usually stuff pertaining to your major/studies), plenty do not (stuff pertaining to social groups).
6. I was confused by the vacation days too. The original rule was "7 days per heir, no days rolling over" until University Life was released. I think the new rule is 7 days for your founder, leftovers roll over to the next heir (e.g. your founder used three vacation days, so your next heir gets the four leftovers on top of their seven), etc. I got around this by simply travelling as little as possible.
7. A fairy-ghost is different from a plain ghost, yes, but they count as an heir only if you don't have their specific ghost type
or if you don't have a fairy yet.
8. Spouses and spares are free to leave (or naturally die, if you're into that sort of thing). It's kind of necessary to fill your household with heirs.