Brake Noob

Pull the rear drum and measure the inside diameter of the drum and the width of the shoes that are on it now and report back. Drum brakes are all measured by there inside diameter of the friction surface of the drum.

Look in your factory service manual to see if you have auto adjusters front and back. I think you would.

As to replace all the hardware or not? if it is in visually good shape, not bent, rusted behond cleanup, missing no real reason to replace (BUT... for the expense it might be worth it to have a base line of known good parts.)

Lastly... front brakes do most of the stopping so it is not uncommon to have larger and wider brakes on the front then the rear.