My main bike is still one of the original 2003 Epic's. The only original components still left on it are the frame and shock now though.

I doubt you'll find a better option than the Inbred. Not only is it cheap but having rack mounts means it's easy to convert to commuter spec.

Definitely need to be 2nd hand to meet any reasonable definition of light.

My 1st MTB had Jett's fitted and they were pretty bad. My wife's bike had Judy TT's and while still poor they were a lot better than the Jett.

On my Inbred I've used both steel and carbon rigids and also suspension forks. If you're mostly riding off-road then the suspension forks will be much, much better – however I do find the carbon forks noticeably more forgiving than steel forks. I'd probably still agree with the poster above that it'd be about a 2 on your scale though.

My Inbred is a sort of general purpose hack these days so for that purpose I find that the carbon rigids suit best. I ride it off-road a fair bit, but mainly on reasonably tame stuff. I'd be happy enough to ride it somewhere like Glentress with the carbon (or steel for that matter) rigids fitted but it'll be less fun and a lot slower than with a decent suspension fork fitted.

Most likely a medium would suit best. I'm about the same height as you and ride a medium Epic, however I did also try the large and felt that would also have been ok.

Also a Tricross sport (on bike to work). Makes a decent commuter/light tourer that can also be ridden off-road.