Ah, so you were one of the patient ones? Hats off to you, because waiting is something I am just no good at. ^_^
I'm glad to hear you've enjoyed it so far and you like the direction things are heading in.
As for your questions:
It depends on the route you are playing - the closer you are to the crown, the more influence you'll be able to have on the conflict, and I want there to be a few different ways to succeed since success is kind of subjective (for example, an ending where the Parisi are very powerful but your marriage has broken down - whether that is a success or a failure would depend on your personal outlook).
The new skills will be dependant on your partner and reflect what you have picked up in the last two years. There is one for each partner and they are permanent. So say you played Leo's route first - the skill you have acquired with him will be unlocked not only for that route but for all routes you play afterwards. I have a rough idea on what I would like the skills to be, but I'll see how my ideas develop as I write the routes.
At the moment I am looking at 3/4 endings for each route with variations available dependant on what you chose in the game (like having children or not as an example).
You can fall in love with Guillaume in the loveless route, but not the route where you are pretending to love him. I am toying with the idea of letting you have another romance option in the loveless route (I won't say who, lol) but it will depend on how the writing goes.
The secret romance is a new character.
Not that bad - I think it's his bar tab that's probably costing the Duchess. It's very easy to be generous when it's someone else's money. ^_^
Thanks for playing