Hello,
Yes they can.
Please see below:
https://www.thesolarcentre.co.uk/products/Solar_Battery_4_Pack_AA_1000mAh-1178-5.html
Hello,
To turn the lights on, pull the pull tab out and then it will automatically come on when it is dark.
Hello,
Yes, this light is warm white.
These are made for standard square posts measuring 3–4 inches (76–102mm). Since 3 inches equals 76mm, a 70mm post may require packing or additional wood to ensure a snug fit on top.
30 lumens
This is 3.9inches, which means the unit will fit.
The batteries will charge via the suns UV ray, there is no USB capability with this light