A:AnswerYes, you can add more devices through the app.. I'd avoid these though and find an alternate option. I wrote a detailed review as to why, mainly a combo between poor battery life and image quality isn't true 2K
A:AnswerYes, these cameras require WIFI to operate. There is no network jack on these cameras to allow direct connection to your network, nor do they work with a wired base station.
A:AnswerThis really depends on how much motion you have at any given camera location. I have five cameras in my setup. Four cameras are positioned over doors and have been running on the same charge for over 5 weeks now. The fifth camera is positioned over my garage doors and sees far more action. As a result, I had to remove this camera and charge it after four weeks.