Firewalla Gold Pro & RBE771/770

Hello all, thank you in advance for any wisdom you may have. 

I have an Orbi RBE771  with 2 RBE770 satellites (wired backhaul, latest firmware) that have been working great. I want to make a significant modification to my network by adding a Firewall Gold PRO device as a router (for Dual ISP, VPNs, etc.) and running the Orbi in Access Point (AP) mode. 

My question is on the design. Ideally, I would like the Firewalla to handle DHCP and routing for the entire network (both wired and wireless), while continuing to use the Orbi in AP mode and with wired backup. I want to avoid double NAT, of course, if possible. 

In a simple diagram, this is what I am thinking: 

My question is, can I get away with this okay? Can the 771 and its satellites be plugged into a standard switch with other wired devices (PCs, TV, etc) and still communicate via wired backhaul?

I could create a dedicated VLAN for the three Orbi devices, but that would require relocating the 771 to a less desirable location (i.e., a basement). Or I could go for wireless backhaul as the devices are in good range for that option. 

Thoughts, comments, and advice welcome.