Philippe,
Unless your brakes and axles have been buried in mud for a long time, I think you will find the hardware will be remarkably well preserved. Study the manuals so you don't break something disassembling the items and then wire wheel or media blast to clean them up. Since you live in FL you may want to paint them but some uncoated primers actually attract moisture like a sponge so be careful. Clear coat with spray can lacquer works pretty well for the protected area you are working in.
I may be wrong but I think you are mistaken regarding lubricant. Original instructions for the transmission and differentials of the older trucks noted that mineral oil lubricant was required. This is not correct for hypoid differentials and any modern hypoid gear lubricant should work. I hope that someone will correct me if I am wrong.
I would use Permatex "Right Stuff" to seal the axle caps. I don't think the gaskets you linked are the correct ones. Don't you have 10 studs on your rear axles? The Right Stuff is a rubber compound that works great without oil seepage and no gasket is required. It is somewhat adhesive and holds up much better than RTV. The lock pins you linked are what you are looking for. You have to bend them slightly to remove them but if you are careful and the previous mechanic has not ruined them already you may not need new ones.
Good luck,
Kent
