remove the brake drums and undo the entire shoe assembly, clean it up with brake cleaner thoroughly (dont let the runoff drip into the soil - its very toxic, dump it in used engine oil instead)
use a touch of 100% silicon grease on the contact faces of the brake shoes (contact faces are the three spots the brake shoes slide on the back plate, do not use regular petroleum grease as it degrades with water and causes the squeak etc.
Use antisieze on the automatic adjusters after cleaning them out first, then use some of this same antisieze on the brake shoe lever points (top and bottom)
At any point in the brake system do not ever use petroleum grease as it can seriously hamper brake performance and also cause severe injury or accident. Change all brake fluid (oil) every year, it takes half hour at max, old fluid absorbs water from the atmosphere and lowers the boiling point of it. It then causes brake fail when you need to stop quick as the fluid boils out the water and creates steam - steam is compressible which means you lose all hydraulic force.
For the rear bearings use rubber seal bearings only.