Catamaran's are very forgiving. If you take the courses you have listed and go with a bareboat in Greece you will be fine. Taking another couple that has more experience the first time is double icing on the cake, cost and experience wise. My wife and I always take other couples on Charters because it's also more fun to share.
My experience - bought a 26 ft grampian (mono) sailed it 9 times over a 4 month winter - sold it, bought a 31 ft hunter, sailed it weekends for a year meanwhile taking asa classes through 105. Took a bareboat catamaran out of the BVI and had an absolute blast. I was the skipper of record although the other couple had owned a boat for 11 years I was better qualified. Most sailors never take classes.
At the time of my first bareboat I had never dropped an anchor, reefed a sail or changed a fuel filter. I knew how, just hadn't ever done it (except in classes).
Now (all of five years of sailing) I own my catamaran - a Gemini 105Mc and sail it single handed or crewed anywhere I want on the Chesapeake. Owning a Gemini is the best thing to happen to me in a long long time.
The best way to get sailing experience without spending lots of money is to simply go down to the docks, join a club and get some experience on someone elses boat. If you are ever in the Annapolis area just holler I'll be glad to take you out (Private message me here first and I'll shoot you a phone number).
Patience Two; Gemini 105Mc #987