French Doors

I second the response from Sid42. Ask your neighbors for suggestions for a good local "handyman" company they use, or check Angie's list. Any decent home improvement/repair contractor can frame in a door, mount drywall, and hang the door with his or her eyes closed. Like Sid42 , I know whereof I speak - I'm a complete klutz, but I have a great home improvement guy that everybody in my neighborhood uses. I may not be handy, but I can speed dial with the best of them. ;)

Don't use french doors and use a standard size door. That way you can treat that wall for a better sound.

French doors look great, but there are downsides. They will transmit sound into the rest of the house through the glass resonating - is that OK? If not, you are better off with a solid core door that seals on all sides with insulation (they make a bottom thingy that seals by pressing downward when the door is closed). This will make sure you don't bother others in the house when they want quiet and you don't. If you decide to get french doors because of their superior aesthetic, make sure that you get thick glass. Thin glass can resonate something aweful.

French doors do have glass which is probably not a very good idea.
If there in no electrical on either side of the rough opening (32 1/2") You can install 2 pocket doors.

I assume that you say "we" just moved in, that the french door is a major WAF. So have a door custom made for the opening. Then install curtians on the sound room side to buffer the reflections inheirant to glass doors. 65} is a little wide but I think some wider trim can allow you to install a standard width door as far as the height add a mock transom or some doors have different variations of a transom built in. Just a thought.