Word is that WiFi on PS4 isn't going to perform as well as an ethernet (wired) connection, but I ran WiFi on mine for many years before taking the time to pull Cat5 to my living room and I really didn't notice any performance problems when on WiFi. During my WiFi time, the wife jumped on with her PS4 (also WiFi) and we ran together just fine on a 50 mbps cable company ISP connection.

ESO in general doesn't require a ton of bandwidth other than when downloading updates. The rest of the time, it should do just fine with two PS4 consoles on WiFi. My advice is to just run with your existing setups, no changes needed, and only worry about performance if a problem develops. Hope this helps.

Honestly, the only thing you'd have to worry about is introducing electronics into the house hold that would create more of a 'haze' of noise, that would interrupt communication between the PS4 <-> Router. This is really a minor thing to even concern yourself with.

From the sounds of it, everything seems normal.

If you ever feel you want more performance from your internet, be sure to look into running CAT5 cables into the room(s) you / your son are playing in and hardwire the PS4. There are neat devices where you can use the power plug on a wall to insert a CAT5 cable into. I have done this with my significant others PS4, as they love to play Street Fighter 5 while I play ESO. Their connection needs to be pristine in order to enjoy the Street Fighter match, I play PvP so I prefer being hardwired for a more stable experience.