You might need a bit of a lift with 265/65-18s on a DII, especially since they are almost an inch taller than the popular 265/75-16s that are used with DIIs (and D1s) with a mild lift. LR3 owners are using 265/65-18s with and without (albiet with varying success) a lift. If you really want to maintain a stock or similar size, and the same performance and durability as the BFG AT, I would highly encourage you to look at the General Grabber AT2 in a 255/60-18. I have bought three sets of them for two LR3s I have owned. They are fantastic. They arent LT rated unfortunately, but I have had them stand up to sidewall gashes and penetrating road debris.
My ex wife's LR3 is still on her original set with 60k on them. I had 40k on mine before I had to replace one because of a sidewall that did ultimately tear (I have no idea how I did it). So instead of having two new ones on one axle and two with 50% treadwear on another axel, I went ahead and replaced all four. I still have the other three good ones just in case I have to replace one later on (seems as if once I get 50-60k miles I routinely damage a one tire). So now I have back ups...LOL
Seriously, consider the Grabber AT2s. I was skeptical at first, but since there were not many options for an AT tire in relatively stock size for the LR3 (in an 18" wheel), I went ahead with the Generals. So far they have been great. I would prefer an LT load rating and a little more tread depth, but I still recommend them.