What a nice collection of parts! Looking forward to watching this come together!
Also can vouch for pins with clutchback method. No issues with them falling off, repositionable, and they will not move or slide at all on your gear like magnets could.
As far as minimizing washing goes, sport equipment spray works extremely well for me ( I use Odor Aid since I can get it at work, but I've heard Clear Gear works very well too). After trooping turn the flight suit, vest and neck seal inside out and spray it all over and hang dry.