I propose to subdivide such possible 3rd party actors to «members of organizations» and «individuals», since they are different cases.
► Organizations could include teams or separate members of local army, police or security, some local militia groups (either aimed to aliens or nonspecific), independent resistance groups... as well as people like "Cult of Sirius".
Individuals are just any people with any of the same motivations: farmer who grabs gun to protect his farm with 12 gauge slugs, police or army veteran, just any punk who decided that aliens are intolerable and it's good time to test some incendiary grenades, criminal elements (they too have life and property to defend, and ready for this more than average citizen), avenger/fanatic, or some kind of "space mind contacteer" who can either actively get underfoot or really fight...
Note that police officer makes the same "typical template" whether in team or alone. Team just can have "squad items": transport and additional weapons (and better armor if its reinforcement).
► Attitude of organization members is defined mostly by relations between X-Com and given organization, though X-Com overall reputation matters too. They affects organization's relation when harmed/saved. (State relation for army or police.)
Individuals have random attitude influenced mostly by X-Com overall reputation and affects state relation.
► Individuals usually behave independently, while organization members will team up if possible.
► Friendly armed forces may either coordinate efforts with X-Com operatives or act on own account. In terror mission local police or SWAT must not wait for X-Com, they'll just take up arms and board their transport, but crash site or "alien spotted somewhere there" is different situation: even if arrived soon, they'll likely to encircle and guard very far perimeter, leaving attack to X-Com (this still can give some long-range firepower, maybe even partially controlled).
► Individual with friendly attitude who was not discouraged (or maimed) in mission can volunteer - i.e. may be added to potential random recruits pool after action. Especially if managed to harm or kill alien. Of course, this rarely applied to organization members (though alien-hunters would see this as a prize and apply always).
Edited by Turbo Beholder, 30 April 2007 - 01:25 PM.