Wow, the new boat route. I think a lot of us might be quietly jealous...
It sounds like you have a handle on how to prepare. I have heard of positive reports from those who did learning cruises with http://www.mahina.com/
before taking their own boats off-shore (both men and women, together and separately). Given the quality of boat you're receiving, the investment could be worthwhile in the confidence and comfort department.
For women only, http://www.tethysoffshore.com/
gets good reviews as well.
For your first charters, many would "stack the deck" and charter in the best possible first cruising grounds (often the British Virgin Islands) in the best possible season. First impressions are important for a lot of family members, and having things go dreamy at the start can make up for less-than-great conditions later on.
Final note: I had an instructor who was found of saying, "At sea, you are the plumber," meaning that every system is your concern and responsibility once you're cruising. You'll have fewer issues with a new boat and new systems, but I've read of less-than-great surprises even with new boats. It's always an adventure...
Have a great time getting ready, and I hope your son has a great time. Meanwhile, I'll try to keep my envy in check.