There are a few of ways to find out what will fit:
Research websites like Bikepedia and Norco.com and check the original spec. You've possibly done this already and found it's of little help.
Pull the cranks off and remove the BB length and diameter will be printed on it. You're looking to take it off anyway.
Remove everything and measure, this will be most complicated and a last resort.
They're your three options, but with a bit of googling to confirm it's easy to find threads dealing with this. Essentially most North American mtbs of this age run a 68/73mm English threaded BB and a 47.5 or 50mm chain line. 2.5mm won't be a significant difference however.
As you are replacing crank and BB you only need to match what you buy, so if you get a square taper BB you need a square taper crank and so forth. The crank determines spindle length, not the frame. Shimano Hollowtech II cranks come with an external BB so always an easy option.