a wiring schematic maybe helpful here....

You'll need a NL/ML converter and you're good to go. 

If you have a C4 Matrix ( Leaf / Control4 branded depending how old) then you have break outs at each end you can simply connect to AV sources.

You also have the option of coming out of your C4 controller.

I have an EA5 with rca output into a pair of Pentas. We just programmed a room called “B&O” you can call it whatever you like, so I can stream all my C4 services and control from remotes / touch screens / iOS devices like any other source. It’s a proper variable output pre-amp, not just line out so can control volume etc remotely as well. These are old Pentas but this would work with any active B&O so long as you have variable line input - I don’t know anything about late B&O but assume they would have an analogue pre in not just rj45?

I have the Leaf branded Matrix as well, this goes to rack mounted receiver amplifiers to run passive speakers in multiple zones.

of course you’ll need amplification for your passives and won’t need for your actives. Your amps should be rack mounted to take the signal from your Matrix they have both at source hdmi outputs to go direct to rack mounted AV and the HDBASET outputs to your break outs so you can have both rack and remote AV

your C4 integrator should be able to sort this out pretty easily.