Recommended Network Configuration

[lleachii]

@outofscope

Please tell me if my thinking is wrong, I am new to LEDE and keen to learn from others.

You're not wrong.

@outofscope

Keeping in mind that I would like to run three independent networks (1 x WLAN, 2 x LAN) with two of these networks going though an OpenVPN connection, could someone please point me in the right direction of modifying my default config file before moving onto the next steps?

Hummm....
See: Separate subnet on physical port #4
And: Use WireGuard interface for specific devices only

You can also make a separate WiFi SSID for the children, and attach it to the second LAN.