Do you have a modem where you have Internet access from your ISP?

Have no idea~

Hum, I don't think it would work.

I don't think the router can be updated automatically. I found a link here that may help you. http://www.tp-link.com/en/article/?faqid=349

What I understand is that the powerline devices can be connected via spur to spur. But you need to make sure they are in the same circuit or ammeter. And devices with built-in surge protector will...

I don't think so. When we say Soft AP is supported or not, we usually refer to the operating system instead of the Internet connection.