I only have detail HE attributes for the current Sonos Group master, which in my case, is always the 'Kitchen Left Sonos' Five. All the other Sonos players (10) and (3) subs do not have any playlist active and their playlist queue is clear and they are grouped with the Kitchen Left Sonos Five. I only have the Kitchen Left Sonos Five as a HE device as the other players are just slaves and do not need to be part of the HE system.
All my Sonos players get their fixed ip address from the DHCP router by their unique mac address. I control some of the Sonos attributes (e.g. volume, mute, next, etc) using the HE device directly from a dashboard of the Kitchen Left Sonos Player device, or I can control it within our Amazon Echo(s). I also have a custom RPi python script that checks and re-groups all my players every hour, saves the current active playlist and player configuration info, etc and restores it when I need via a voice command. This is because I have a Sonos Arc and it tends to want to separate from the group and other issues.
From what I read, when a Sonos player needs to access the internet, it does so directly. However in a Sonos Group, the first member fetches the stream on behalf of all the members, and distributes it locally to the others. You can check your Sonos configuration details by browsing http://ip_address_of_a_sonos_player:1400/support/review
For many transactions a master controller will access the internet directly itself, but sometimes it gets the Associated ZP to do so on its behalf. The Associated ZP is the Sonos player a controller uses to talk to the system in general, and is not necessarily the same as the player currently being controlled. The Associated ZP initially selected is the first player to respond to the SSDP multicast when a controller starts, so it is pot luck which gets chosen. It can change subsequently.
Here is a snapshot of my Sonos System's Kitchen Left Group Controller and Master.
Associated Product: 10.0.0.27
Play:5: Kitchen (L)
Sonos OS: S2
Version: 14.2 (build 67126143)
Hardware Version: 1.13.1.7-1.2
Series ID: C100
IP Address: 10.0.0.27
WM: 0