You are much further along than I was in anticipating what you will need. I had my D800 in hand when I noticed that my handy D7000 remote shutter release approach was not going to transfer. I only wanted remote shutter release and preferred to keep the flash triggering capability separate.
I bought an RFN-4s Wireless Remote Shutter Release for my D800 that I've been quite satisfied with. I notice there are less expensive alternatives mentioned in the very relevant topic below,