I'm still confused as to why they don't simply combine this idea for a Disney streaming service with Hulu. They will own 2/3rds of Hulu if the Fox deal is approved, and they could simply buy the other 3rd if they wanted to, they can afford it. Hulu already has an established subscriber base of 20m, with the power of exclusive Disney movies and shows, and an expansion into more countries, Hulu could become a powerhouse able to compete against Netflix.
It's going to be really hard for them to sell people on a separate $10 a month subscription just for Disney movies and Disney shows.
Anyway, to answer the questions in the OP:
1. Would be smart for them to do that if they want to get alot of subscribers, though it might hurt blu-ray and digital sales.
2. Wouldn't surprise me if they did.
3. I could see them doing that.