I'd loosen the fork and measure your fork's diameter, to be absolutely sure to buy the correct size fork.
The 1" forks aren't as plentiful as 1.125" ones. Most 1" forks are relative inexpensive. Try not to get the cheapest one. I'd go for a popular, quality fork, if possible.
Regarding brakes, ya might consider hydraulic brakes. They're a little more expensive than cable discs.