Multiple EX6400 Access Points with the same SSID over MOCA

I have FIOS 1GB service with the FIOS new G3100 Router and it is set on the ground floor of the house.  Service is Ethernet cable from ONT to the Router. There is wifi service and ssid is broadcasted.

To enable good 1GB service in the house I decided to leverage the existing Coax cables that were already in the house for TV service and use MOCA Ethernet adapters (Actiongear ECB6200) to connect to two EX6400 (One in the Basement and One in the top floor). I assigned the same SSID that is for the G3100 to both EX6400 5Ghz and put them on different channels than the main Fios is (2.4 radio is off on the EX6400).   Everything seems to work but how can I tell the network is optimized?  1. Both EX6400 set to use dynamic IP, how each one of them is managing the network connection as devices move from one access point to the other? (or all together conect just to the main router?) 2. How can I tell that by having this configuration I don't cause additional interference? There used to be a way to control the strength of the signal when configuring the EX6400 Access points but it is not there. 3. I disabled the 2.4Ghz on the EX6400 and kept 2.4 only on the FIOS which is using one SSID as SON, also disabled the "Smart Connect" option, forcing all my devices to connect to 5g even if not needed. Should I put it back and trust the system to provide the best connection to each device?

Thanks for the Help.