About PSG
You do have a luxury problem now with this selection. I think this might be the best squad a club has ever had. The unapproachable Barcelona of 10 years ago would not be able to cope with that either. If you play with all 4 strikers, that is a feast for the eyes. And a problem for the trainer. Midfield and defense ditto.
In the league there isn't all that much competition, really the only time the back players would be exposed would be in the Champions League if they play with all four, although I think they would probably take a more balanced approach in the Champions League. However, in the league I think I would expect most of them to play week in, week out. I'd also predict that there's going to be a record breaking amount of goals scored in the French league.