Given the issues that go along with wireless equipment, I would highly recommend a hardwire solution. You said that the
orchestra was going to be upstage which is why you have this issue in the first place. If this is true, I don't see how cable runs would be a problem. if you run your cables along the US wall to either side of the
stage and then down the side walls, along the
proscenium to the lip of the
stage it shouldn't be in the way of any moving scenery (unless you have scenery that moves around US of the
orchestra.
A hardwire
system will give you far fewer problems and will be a lot easier to troubleshoot when things don't work. Generally, most things wireless that are worth using will cost more than you really will want to spend. A hardwire
system can be very flexible, and chances are can be interfaced with a wireless
system if needed in the future. Also, for the cost of a worthwhile wireless
system you could get much higher quality wired video gear.