1. ARB OME 40mm kit, then the extra bits to make it into a Suburban 3.5" kit.
2. Very much so.
3. ARB in Richmond did the first bit, USA 4x4 did the extras.
4. 245/75R16 Cooper 'New' STTs on standard Sport steel rims.
I wouldn't bother with anything other than the HD OME springs. I believe CRDSTU is working with ARB on some extra heavy duty front springs specifically for the CRD. I'll be after a set of them probably, even though it's not a CRD, to hold up all the extra crap I've got bolted onto mine!
Unfortunately the Suburban 3.5" kit is no longer available. But you can fairly easily make up your own kit out of separate parts that will approximate it. Check out what makes up the 'Frankenlift' that the US L.O.S.T. boys (and girls) swear by.
And I'll second (third? fourth?) the advice to join a Jeep club. The training you get (for free!) when you join MJOC is invaluable and the trips are very professionally run. Always handy to have someone available to pull you out when you have an "error of judgment" moment.