VNC server configuration setup confusion

I have two Raspberry Pis: Pi 3B+ and Pi 4B.
New Gateway: Comcast XB7-T (Technicolor CGM4331COM)

I had no problems with the VNC server and Viewer until I got a new gateway.

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With old Gateway
I set static addresses in router for both Pis. While booting both Pis used the IP addresses set by router.
Also the router used the hostnames set by each Pis configuration.
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With new Gateway
I set static addresses in router for both Pis. While booting both Pis ignored the IP addresses set by router and picked their own.
Also the router ignored the hostnames set by each Pis configuration. It picked old hostnames that were used previously by the Pis maybe a year or two ago.
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To fix the IP address problem I had to edit the /etc/dhcpd.conf file for each Pi to add static IP addresses for wlan0.
I don't know how to make the router accept the names configured for the PIs. For now to avoid confusion I change the names on the Pis to match what the router wants them to be.
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In VNC viewer:
Old gateway: both Pis show up under both Address book and Home Team.
New gateway: both Pis show up under Address book but not Home Team.

However, I can still connect to both Pis using the VNC viewer.