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...

Your Wi-Fi router is a dual band one? If not, it is not necessary to buy T4UH which is a dual band Wi-Fi adapter.

By the way, what's your expected Wi-Fi range?