If I am flying and ticketed on business class, can I use the club lounge

Yes you can

You must be a member, or possibly you might get in if you're flying internationally.

Yes, of course you can.

I am sitting in flagship right now. Flying JFK to Rome in Business. The answer is YES.

There is a Business Class portion of the lounge.

Yes you can. It depends on the route, if it's Mexico only to Mexico City, Caribbean routes aren't part either. And no it is not just for first class, only the flagship dining restaurant ks for first class only. I fly to GRU all the time in business and always use the flagship lounge at JFK or MIA https://www.aa.com/i18n/travel-info/clubs/flagship-lounge.jsp

No. You can use admirals club if international, or one of the three triple class trans con routes. But flagship lounge is only for first class.

I think so