There was a front formula that came out mid ninety's,it had a pre IS mount on it that fitted older bombers,i think up to '96 ,the mounting holes were i think 47mm as apposed to the 51mm that IS mounts are.If you have that one you may be stuck for an adapter ,i looked for one for years before giving up and selling the fork on
Shortening the hose should pose no problems.
Never used discs before?
Boy. Are you in for a BIG suprise ,at last ,brakes that not only work ,but inspire.
You're going to start questioning why you have canti's on any of your bikes
I've not even used v-brakes before let alone discs.