"Should I just replace the shoes and magnet. Seem like its cheaper to just get the whole assembly."
Need more info...what's worn and how much? Only you now the answer.
"I am also going to replace the inner and outter bearings. Same question should I just get the bearings or get the whole drum. My current one seems in good shape."
If they're in good shape why replace? Sometimes its cheaper to buy complete assembly. But you still have to pack the bearings and adjust brakes.
If your thinking is...you'll get new assembly's so you know what you have might give piece of mind maybe.
We all do it a different way...I'd make sure no grease getting on brake shoe and brake was adjusted right and when I was packing bearings I would pick up a spare bearings and cup and grease seals for one wheel and keep it with you in dust proof container. Do a quick temp check with IR gun when you pull over every so often.
But we all do things differently.