What does your zone A look like is it completely filled?
From help file:
Zones may or may not overlap. This does not affect use for masking, but it may affect the
way that object detection functions. An object is considered to have been in or traveled to a
zone if the center point of that...
You cannot have constant streaming with no wires unless you have solar and a large battery. You can build or buy your own solar kit to power any camera. You dont need a wifi camera, use a cheap wifi bridge.
Dahua sells solar kits but a google search will show many other alternatives...