Aliens: Fireteam Elite 2 Co-op Player Count
Aliens: Fireteam Elite 2 supports squads of up to four players, expanding the first game's three-player structure.
Quick Answer
Aliens: Fireteam Elite 2 supports up to four players in co-op. You can deploy with as many as three friends, then coordinate class jobs, weapon ranges, and ability timing so the extra Marine adds coverage instead of duplicating the same role.