Have seen a similar situation in cricket with the England cricket team. Vaughan skipper and Flintoff vice captain. Vaughan was a good captain and decent player then gets a long term injury. Flintoff takes over and Strauss becomes vice captain. Flintoff was a good player and poor captain, stupidly bowls himself 50 overs in an innings v SL at Lord's and ends up missing the win and gets a medium term stress fracture type injury from memory. So Strauss takes over the captaincy, and like Edwards here, does a great job, looks like he was born to do it, team seems happy despite the absence of two leaders who are two of the better players. What happened next is the worst mismanagement of leadership roles I can recall seeing in a professional sport's team.
After a few months or so Flintoff comes back from injury. So the hierarchy decide foolishly to overlook the fact he has already proven beyond a shadow he couldn't captain a toy boat in a bathtub, and reinstate him as skipper, losing all the good dynamic built up under Strauss's very able captaincy. This was bad enough, but next thing Vaughan has recovered from his knee injury but has no form as a player whatsoever. So they decide to bring him back as skipper in all formats. He basically never plays another decent innings and is now in charge of a very confused team, which malfunctions badly. Strauss loses all form I would say in part due to disillusionment at being cast aside as leader.
In the end Vaughan retires from a sinking ship, and Strauss is reinstated above Flintoff and lo and behold the team starts to function again.
Now there are differences in this situation because Riewoldt(or Rance if he returned) would likely make very decent captains, they have proven their leadership qualities in recent seasons. I do believe however it is worth considering not rigidly following the original hierarchical structure when you clearly have a new and fresh dynamic functioning well. Also, Riewoldt will have plenty on his plate getting some form back and developing a new role he has to adapt to given Lynch's presence.
I would say stick with Edwards as skipper. Fortunately the team seems to be blessed with good on field leadership options, and all of them come across as happy to be selfless. There is some very watchable(and effective) dynamic that has been brought to this team in the last two weeks though, and both Edwards' playing role and his leadership seem to be at the centre of that. I have faith in the club making good decisions, but it is not always as easy to choose between apparently good options as it may appear.