You are a good employee because you are considering the needs of the employer as much as your own wishes...
As far as November 20th and December 6th, you had asked before the switch plus I would think that the employer would consider your brother's welcome home to be a very important occassion.
As far as January 1st-3rd, you had planned the trip before you knew about the switch.
The only thing I would worry about is: Will they say "No". I really hope they grant all of your requests. I have worked in places where they have said "No" to some of my time off requests. It would make me angry! I want you to be happy and enjoy all of your special plans.