Arlo - Pro 3 2-Camera Indoor/Outdoor Wire-Free 2K HDR Security Camera System - White

Yes, they will store power and work at night. The solar panel needs to be facing some sort of sunlight during the day to maintain the charge. You can use the phone app and click on the device and device settings and it will show the percent of the charge and a symbol if it is charging at that moment. There have been two times that I have gotten the notification that it is too cold for my battery to charge. But even so, it has still charged later in the day. They have been installed since Dec 27th and they have remained charged and active during both day and night. Maintaining 97% to 100% daily. The lowest percentage was during 4 days of rain and clouds which for a short period of time dipped to 90%. The Arlo Pro 3 camera with the Pro 3 solar panel works and maintains its charges far better than the Arlo Pro 2 and Pro 2 solar panel.

no arlo wants you to pay them $30 a year for the monitoring service

Yes you can. Each camera has its own settings you can adjust. I have been enjoying these camera very much and highly recommend them.

Yes, there is a USB port that you can add a hard drive to. Its next on my list.

Comes with mounts, I bought the 4 camera setup so I got 2 screw-in mounts and 2 magnetic mounts. I purchased additional screw in mounts from amazon for 12.00( 3 additional mounts) just so I would have enough of whatever mounting system I wanted to use. I also purchased 4 25 ft charging cables from amazon( 28.00 for 2 cords) and plugged in the new cameras the new cords attach at the bottom magnetically which is very easy to work with and very convenient. Constant power on the cameras allows all of the nice upgrades to work like the 3 second look back feature no more missing what motion triggered the cameras