If you plan well then I don't think fast pass is required, and in your ticket you can avail the facility of virtual queuing with a token that they give. Avoid weekends and reach before the gates open and stay till the end to enjoy the parks to the fullest.
Disneyland HK is better than Disneyland Paris. I suggest you do it only if you have sufficient number of days in Paris. Paris is so big, there's so much to see. I wouldn't recommend spending a day at Disneyland.