couple of Questions for a new 2001 discovery I I owner.
 

1) My dome lights are not working at all. I have checked fuses and bulbs and they all appear to be fine. Any advice on what to try would be nice.
2) I just ordered a 3" Terrafirma suspension lift from Justin @ Lucky8 and also 33"/10.8"R20 Nitto Terra Rappler with a 20x10 XD Monster "Matt black" with a negative 12 offset which will give me a about 4.75inches of back space. Should I feel safe that these will work with a little trimming.
3) when I put the car in reverse I here slight rattling noise coming from the the front. Also sometimes when I put it in reverse it takes a second to engage or I will go back to park then to reverse and it will be fine.

Dome lights? bulbs, fuses, or a bad ground wire to them, only thing I could think of.

Check the driveshaft for the front, if it doesn't have greasable fittings then you have to rebuild it with greasable u joints. They fail and cause bigger problems. My driveshaft makes a vibration when in reverse also, because my front shaft IS bad.

You should be fine with the 33's on a 3" lift, maybe minor trimming of the front bumper because that thing is god awfully large. I don't think you'll really need to worry about axle strength or diff strength because they are on 20's and probably will never leave pavement :D

Thanks. It probably won't see much mud but a nice white sand beach or a trail back in the woods headed to a stand. I'm sure if I lived a little further north I would be all about the trail ridding and rock climbing but the most I have around hear is a poorly made boat ramp.
I had to have the wheels made from blanks because of the lug patttern and the guy selling them seemed really confused about the offset. I did some research and decided on a 10" wheel a -12 offset would be better than what he recommended +35. Hope I was right.