you cannot login with admin or cannot update the firmware? Try login from both screen and web interface

All the lights are off? Did you setup LED control? Does the extender have the same wifi name as your router's? If it has, it's better to connect your computer to the extender with an Ethernet cable...

Hi, what's the model of the AC1750? What do you mean pairing Echo with it?

I just see a new HomeCare Parental Controls on tplink, http://www.tp-link.com/en/faq-1771.html.

Good ideas! I think you can send a feedback to TP-Link support.

Never meet this issue before. To ensure the security, you can setup mac filtering or access control on the router.