Olofmeister was the star player of fnatic before he left, so yes he was a star. Rain was the star of the older FaZe clans so he was a star, NiKo was the star of Mousesports so he was a star, GuardiaN was the best player of Na Vi so yes he was the star, and karrigan was a former star in 1.6 but in csgo he was considered one of the best IGLs of all time.
4/5 players of that team were stars, yet it basically failed. Roles are in the game for a reason, they aren't just some concept made up by some kid and everyone decided to follow them. In FaZe all these stars just transitioned into their own roles, rain was a hard entry now, NiKo was the star player, GuardiaN was the secondary star, Olofmeister went from a star to a support just for the team to function, and karrigan went hard-core into becoming bait/support for this team.