I too am a little unclear about the initial question, but the first thing I would want to know is what format the source material is being supplied in and what physical audio outputs that will appear on. So is it, for example, SPDIF (optical or coax) or embedded in an HDMI signal or 6 discrete analogue channels. Once you know that, you can then decide whether your desk already has the appropriate input(s) or whether you need some kind of decoder/de-embedder between the playback device and the desk.
The other common misconception is about the LFE output. This is not a sub-woofer feed. It is interned to be used for low frequency effects only. However, if your 5 'full frequency' channels do not have the capacity for reproducing the required bass response, the LFE speaker can 'double up' as a sub-woofer; this is achieved by high pass filtering the feeds to the 5 'full frequency' channels whilst simultaneously combining the 5 'pre-filter' outputs, feeding those through a low-pass filter and mixing this signal with the LFE channel. In other words, a bit of clever routing/speaker management may be required here.