1. That's a decent-size conference room, and depending on the content to be displayed, 85" displays may be too small. We routinely install 113"+ screens in conference rooms

2. Decide how many source inputs you will provide so you can size your AV switcher. We typically install HDMI/VGA+audio inputs in the rack, in a lectern, on the wall, or on the table trough cable cubbys (Extron/Crestron). An HDMI/VGA input can take one or two inputs depending on whether the transmitter can (auto) switch between them. We typically use Crestron or Extron presentation switchers (control system plus + switcher) or a control system and a separate switcher. You can get switcher that have Cat5e extender inputs and outputs.

3. You will need a good DSP and size it for the number of inputs (wired/wireless mics, program audio, USB from a PC, line inputs from a VTC codec, etc.) and outputs (amp, VTC codec, USB to a PC, etc.) We use Biamp, ClearOne, and Extron DSPs. Crestron has one now, but we haven't used it yet.

Joe Gordon