Just purchased the Deco X20 3-pack but don't have the system yet. Haven't found much information with details to answer my questions.  Can anyone help?

I run pfSense as my DHCP server and firewall.  Can the X20 have DHCP disabled and function properly on my LAN?

As far as logistics, one node will be placed upstairs where my cable modem, pfSense appliance and NAS are running.  The main floor is our home theater and needs to use WIFI backhaul, and will be connected to a switch that also has a HDHomerun tuner and media PC connected.  The basement will also need to use WIFI backhaul and will mainly be connected to a Rpi.  I have six WIFI cameras located about the house.  All three floors need good WIFI coverage (2,500 SQFT total).  Each X20 node will basically be placed in a vertical plane in one corner of the house.

I'm looking for system stability and only need the upper floor node to have a rock-solid connection to the main floor (for HD streaming).  For reference, I've been using two Asus RT-AC68U routers running in "AIMesh" mode.  This setup is not reliable, with three or more disconnects a day.

Did I buy the right Deco system?  Would the M9 Plus be a better choice due to its maturity (don't need ZigBee)?  Thanks for all feedback.