I’m sorry, I still don’t understand how things are connected, and what role the GS3100 plays. In the diagram you did post here, you show only a single connection to the GS3100 (no cables connected to anything but the CCS326).
If you are an “extra class ham also and have been in tech for 30 years”, haven’t you ever had deal with poor problem reports and troubleshooting? Specific details and a precise problem description will help you get an answer.
Maybe I am using too much jargon, when I asked ‘Does the “FIOS router” need to have a direct connection to the L2 network the FIOS ONT provides?’, I meant “does the GS3100 has to be connected to the same local area network and subnet that the FIOS ONT provides. In other words, does the GS3100 expect to get its ip address via dhcp directly from the ISP?”
You stated “Right now, everything works well”. So what problem are you trying to fix? You state “So, I thought maybe move the G3100 to it’s own port on the hex. Then I wondered if maybe I should put the AP on it’s own hex port – for the purposes of improving performance.” Can you explain why you think that would improve performance? If you can’t, don’t change anything until you can.
I see no reason to making changes without having some good reason, and with a good expectation that the change will have the desired outcome. How To Solve It
I also don’t generally recommend using your primary router to learn with. Much better to get a dedicated router or use GNS3 or EVE-ng to emulate routers to play with. The Network Berg has some good intro videos
New to MikroTik? An introduction for you!
EVE-NG Videos playlist
Since I am evidently not communicating clearly, perhaps there is someone else that is a better mind reader than I am that can assist you.
I expected you to post more info, like your /export on the hex and the CCS326. And an up to date diagram.
From your response, it isn’t clear to me that you even looked at any of the links I posted.