I am not familiar with Linux. You can check the GPL in website below. http://www.tp-link.com/en/gpl-code.html

I have a M7350 seems there's no White list. But I think Black list is much easier to set. If there's unknown device connected,I can block it. And there's wireless password,other's may not connect to...

Do you mean you want to connect to a front wireless network and share the network for other clients? If so,MR3020 can do the job.You can check the settings here....

You can try to find this router,TL-MR3020. It support 3G/4G,WISP and AP mode.

Hi Jeff,you can log in the manage page and check the Status. The internet information are shown there include signal strength. It's shown as percent(e.g.60%).

Since it's a product with battery,I think it's better to charge the battery and use battery to work. It will be more stable I think.