I get 6th men lingering with the starters but multiple bench guys being in at once is absolutely the norm.
Multiple isn't the same as four or five, though.
For instance, look at real basketball. 8 of the 9 most used lineups included Sam Hauser with 2+ starters in the game. They're playing alongside other one included Tatum and Horford, with no data available regarding whether Horford was a starter that game.