1) Yep, that's the easiest way. You'll obviously have to disconnect the brake flexi hoses and steering/track rods too but once done the whole shooting match will pull out of the axle casing.
2) There is a specific type of grease, part no. STC3435 Land Rover specified for later vehicles.

I have run it in my 2a 109 for years without issue, and contrary to popular belief it does seem to get everywhere and lubricate OK. Normal grease will NOT work, it must be the right type.
3) No more than any other bolt. Wire brushing and soaking in penetrating oil several times the week before you want to do the job is always worthwhile.