Brake fluid, now there is a good debate. I would say that more depends on breaking style and if there were any issues with the brakes before the job. It sounds like a good rule of thumb, but unless the fluid burnt/boiled from extreme breaking or a hung pad I can't see the fluid being bad. I suppose better safe then sorry. I think the average Joe runs a higher risk of introducing an issue to the break like from improper bleeding/flushing then by not changing fluid under normal conditions.
On the frozen calipers, I was concerned about that when I had difficulty with the pliers on my gen 1 mz3 at over 100k. I got super paranoid with the normal floating pad setup on the rears too. A few thousand miles later though and all seems just fine.
I come from German cars, every 2 years mandatory fluid change for the brakes. If you are tracking a car, they want it changed every year. (there are reasons for this) Brake fluid is hydroscopic, it attracts water, once it becomes "saturated" with water, the boiling point drops and things start to rust on the inside of your braking system. Both are not optimal things to happen. Fluid is cheap and it is really not that hard to change, do your self a favor and change it!