Can I use a standard pvc new work box for receptacles/ switches, in an outdoor patio wall that will be enclosed? The wall will be completely sealed and covered in stone so rain, snow, etc. will not be able to enter the box(es).
As long as it is out of the weather as you describe then standard boxes, devices and plates are fine. This installation sounds no different than a garage for instance.
Now, if this covering is voluntary, as in only on sometimes, then an inspector could very well consider this a damp or even wet location due to the fact that in some circumstances the area is likely to get wet. As in an unexpected rain storm while you are at work. If this is the case I would treat the area as damp, with outdoor covers.