Installing Ubiquity UniFi infrastructure for the 1st time

I have been tasked to fix a problematic network infrastructure at a small church 7000 sq ft 1 floor building with many rooms. Currently they have no proper network setup other than Spectrum Business 200 Mbps coming in to their provided WiFi router with attached VOIP phone bundle. They have a multitude of various models of WiFi extenders throughout the building. They have 2 8 camera CCTV DVRs for security cameras 19 cameras in total some 16 wired to DVR 3 WiFi. They also have SimpiSafe and HVac thermostats on WiFi.

Here is what I was thinking to do:

Internet---ISP---USG--- UniFi Switch 16 150W---UniFi CloudKey----UniFi AP HD 3x

I was thinking of staging all of this in one area setting it up testing it and the deploying it, i.e. placing the APs in their areas and running cables. What do you think?

Also, regarding CCTV DVR boxes, 8 cameras per box wired and then the DVR is WiFi, but if there is a NIC on the box I would prefer have that wired and connected to the switch. Agreed?

Please reply with your advise and help, thank you.

-Gary