I think we're playing affinities correctly, but I guess I should ask, just in case:
Can a single affinity be used for multiple items? i.e., If a survivor has 1 blue affinity and two items that each require 1 blue affinity, does the 1 blue affinity "unlock" both items? Or would that survivor need 2 blue affinity (1 for each item)?
Yes, each affinity can count towards any number of affinity-requirements for different gear.