So... In terms of Usage rates, which admittedly are just another stat.
Fox in his prime at Sacramento had about a 30% USG rate, this year at SAS he was at 26% USG.
Victor was at a 30% USG rate this year.
Castle was at a 26% USG rate, although he was at about a 22% USG in college.
Dylan Harper was at a 29% USG rate at Rutgers.
USG formulates how many possessions a player finishes, whether a field goal attempt (whether it goes in or not), free throw attempts, or a turnover. It's this: 100*((Player’s Field Goal Attempts)+0.44*(Player’s Free Throw Attempts)+(Player’s Turnovers))*(Team’s Total Minutes)
Obviously something has to give, if all four of these players start. (Harrison Barnes was at a 15% USG rate this season.) I'd expect Wemby's usage to dip at least slightly. His first year, he was at 32% USG, so already dipped about 2% as Castle and Fox became more involved. Castle, I believe, can handle less of a load, more like his college rate. Fox may have to be happy with a bit of a reduced role -- his scoring/shots went down already over his Kings days, and I don't expect them to go back up.
If you stagger guard line-ups, you get more touches, but I don't think it's going to make-up for the shortfall. I don't expect Harper would be getting that many finishing touches right away (30%), but the issue will persist until something gives along the line, such as Fox, Castle, or Harper getting moved.