we plan to leave on a RTW on two africa twins next March, and two friensds of mine are currently driving their AT's to Capetown (from Europe)
Think you have everything you need.
We have done an overhaul on our fuelpumps (the electronic mechanism), and I have one spare per bike.
Rectifiers: change for a proper aftermarket (heard bad stories about Tourmax...) and take your original one as a spare.
I take throttle/choke and clutch-cables, as well as a set of levers.
Have put in a new battery in mine; preventive. And checked the brake disc thickness; as we plan to drive 2-3 years this should be okay... quite expensive to change!
Wheel bearings: I do not change them preventive, but check them at every tyre change. Standard sizes, so you should be able to get them everywhere?
For the rest they are quite rigid!