Are there a lot of mansions in Amenia?

It depends what you consider a mansion. Most people are unaware of the housing stock that is tucked away in the more remote areas of Town.

Not in my opinion. There are certainly some expensive homes, but the average home price isn't ridiculous. Amenia is a pretty slow hamlet/town, with a lot of open country around it. I'd say you won't find an excess of mansions.