No problem with your understanding. Most people prefer to use same SSID and password as the main router.

I consulted TP-LINK support team on firmware issue and got a reply as below. The firmware of powerline adatpers like PA6030 is composed of PIB and NVM. A new firmware released may not upgrade PIB and...

A piece of advice for you. Pair your powerline adapters or set the same unique network name for them. There is an instruction. http://www.tp-link.com/en/faq-258.html

Did you download the web plugin here? NC200 is connected to the router by cable connection or wirelessly? What's the version of your IE? https://www.tplinkcloud.com/download.php

This issue is mainly related to network environment and I don't think it is a bug. Maybe TP-LINK people can explain better and help you to further look into it....

How is it going now? My friend helped me to test by iPhone 6 and 6+ and we called each other but no problem at all. What's the MAC OS of your iPad Mini? Any other apple devices you can test in your...