I'll just second other's great advice. Those questions are perfectly fine, in fact quite good qualifiers. No sense in asking them, though, for the schools not on your son's radar and if you have no intention of attending.
Continue to let your son handle the dialog with the HC's and RC's. But, monitor and advise and set the rules/parameters with him where necessary. You are likely paying for much of his college. So, anything tied to that aspect warrants your direct involvement.
There are other threads on this subject. You can search past threads here as well.
Hope his visits go well.