Which is the best MTR ticket to purchase?

Well, according to your travel situaiton, you are suggested to buy HK Airport Express Travel Pass. This card has one or two Airport Express single journey(s) plus 3 consecutive days of unlimited travel on MTR. It's suitable for you.
1. Take airport express to HK Station first. Then walk to the Central Station and take Island Line to Tin Hau Station, Exit B. After arriving, walk to the destination directly.
2. Take Island Line at Tin Hau Station, and get off at Central Station. Then transfer to Tung Chung Line to Tsing Yi Station and take Disneyland Resort Line to Disneyland Resort Station, Exit A. After arriving, walk to the destination.
3. Take Disneyland Resort Line to Sunny Bay Station first and take Tung Chung Line to Hong Kong Station, Exit E2. Then take airport express to the airport directly.

You need to visit these places as soon as possible. Otherwise 10 hours will be tight for you to tour.