The master cylinder is the only thing I'd take care with. Just a dribble of fluid in it and stored so it sits in its natural upright position. Wrap in oiled paper like the manufacturers often do to stave off rust from humidity. Master cylinders tend to last years and years, expect it to sit unused a very lond time. I wouldn't bother myself. Fresh rebuilt ones aren't that expensive.
I keep a couple of water pumps around. When I need one then I have a trade-in core for the parts store immediately instead of having to take mine off before going to the store. I neither know nor care whether they are good or not, not worth the chance.
An extra alternator and starter are VERY handy to have stashed away. New/rebuilt ones cost markedly more than they did some years ago.