Second v2 hub goes offline whenever my phone arrives!

Nope

Nope, feel free to do a port scan to verify, but the last i port scared my hub it had no open ports.

There is only graph.api.smartthings.com to check on your hubs.
FAQ: Logs and SmartThings - An intro into figuring out what went wrong

You may also want to contact support, support@smartthings.com