Maybe it will work but it is not recommended to do so because it may shorten lifetime of your switch and cause damage to it. Such kind of damage is not covered by warranty.

So powerline adatpers cannot communicate with each other now? Reset them first. http://www.tp-link.com/en/faq-312.html And then, pair them again.

You are so considerate... WN8200ND is a high power adapter and it supports 2.4GHz only. Maybe it is better than WN822N... http://www.tplink.com/en/products/de...-WN8200ND.html

Where did you download the tool? What's the operating system? Try the one as below. http://www.tp-link.com/en/download/TL-PA4010_V1.html#Utility

What's the model number of your dongle? Is it in the list as below? http://www.tp-link.com/en/support/3g-comp-list/?model=TL-MR3420&location=1151 Did you try to contact the support team to see if...

As far as I know, guest network has no such a feature. You can block it to access local network or configure bandwidth control. That's all...