What do the various "Can Appear as" options do in the Character Pool creator?
Can Appear as Soldier allows for characters to potentially appear wherever there is an opportunity to recruit soldiers. This includes mission rewards.
Can Appear as VIP lets characters to appear as Resistance VIPs in the rescue missions given to you by the Spokesman. Once rescued, they can be either Engineers or Scientists.
Can Appear as Dark VIP can cause them to appear in Guerilla Ops as ADVENT VIPs, who can be captured or killed.