AW4 is a very strong transmission and will take just about anything you throw at it so long you keep it cool.
Axle wise, 4.56 is a good ratio for you. On a front D30, 4.56's still allow for three teeth on the pinion to be engaged on the ring gear at a time. 4.88's and you'll drop to two teeth engaging at a time. Just helps with strength considering the ring gear size on a D30.
Does your XJ have the high pinion D30 front? A lot of the XJ's did, which also helps. A high pinion arrangement is stronger in front differentials when compared to a low pinion set up.
Do you plan to run lockers? If you do, it would be better to install them while gearing the axles. 33's will live fine with a lunch box style locker and if this is the route you go you'll still be able to do them later. This said, if I was the installer for your gears, I would much rather do it at the same time. The front you'd have to pull the carrier to install the locker. I'm not a fan of pulling carriers following a gear setup. I know you can, and I have on my TJ's D44 rear, but it just makes me uneasy.
I've done quite a few of these. If you have any other questions, let me know.