Any item that isn't class restricted should be equippable any time by any character
Since we can interchange weapons and resource materials between characters, why make us go through multiple load screens to place and retrieve things in the vault?
At the very least, these items should be equippable in orbit on the ship. Basically, everything except armor would be accessible via a vault on the players ship. This would alleviate vault apace issues and also prevent multiple loading screens just to switch a weapon to another character.