Are there cases of people with high cholesterol living long, healthy lives?

Yes. For sure. High cholesterol is only one of many risk factors and, the cholesterol that we measure in clinical practice isn't even the whole story (ie, what appears to be high may be non-injurious when it is sub-typed - which is usually only done in specialized research studies). If your family has good longetivity and you're controlling other risk factors, don't sweat it.
Yes! There are many risk factors for heart disease, and high amounts of bad cholesterol is just one part of the puzzle. Sometimes people with "high cholesterol" have a high total cholesterol because of a high amount of good cholesterol (hdl-c). In this case, you are actually protected from heart disease. Find a lipid specialist near you and learn more. Go to lipid.Org to find a lipid dr near you.