Mate, just found your post.
Its actually safer to have a look at your bearings to get the right numbers for them, though they are basically one of two types but looking will make sure..... to make the explanation easier go here
https://www.caravansplus.com.au/guides/how-to-identify-check-axle-bearings-a-50.html it saves me a lot of typing.
No need to dismantle the inner bearing, just by using the number on the outer bearing will enable you to buy a kit. Repack the bearing wrap back up in the paper and box then Vac Seal into a bag is the best way to keep them schmicko, also stick a pair of surgical gloves in the bag.... I only ever carry one spare bearing with me though.
Brakes parts are pretty universal, just need to identify if its a 10" or 12" hub, you don't want to go about carrying spare drums as the drum is actually the wheel hub, heavy in both weight and wallet... I have bought from this mob good stock and prices, the link has some good info also
https://www.couplemate.com.au/electric-brake-parts/
Also don't rely on what someone else's van has fitted, it may be the same model but sometimes not the same bits are used.
If its just for travelling spares then one set of bearings, maybe a wheel stud or two, small can of bearings grease, any old HT grease is okay, spare split pin, big shifter which will fit the nut. I wouldn't bother with shoes, drum/hubs or magnet if they give a problem just isolate and fix it at next big stop, rare to have dramas and be surprised what some of these outback places have on the shelf at great prices. Most important though is to know what to do but it is handy to have some spares for a mechanic to use belts, filters always good............... A puncture repair kit is in valuable along with a compressor.