Electrical parts will last forever if kept dry. The master and water pump will fail eventually and you'll have sotred them for years for nothing. My last water pump was $59 new (not rebuilt) and $16 for a rebuilt witout exchange. My last master was under $20 new.
Can't imagine what you'd get for used if you sold them, or if anyone would even buy them. I'd get neww and not worry about issues later. Save the storage space for parts that store well.