Every job is different. Some jobs are flat rate whereas others are dependent upon time and material used or based on an hourly rate. All after-hours work is hourly (OT) plus travel. The best thing to do is call and we can discuss your project and the rates so there are no surprises.
A ground resistance reading needs to be taken at the ground wire/ground rod with a special meter. Tight connections do not guarantee an acceptable reading (below 25 Ohms). Above this reading, surge protection devices won't work well either.
Anywhere from $10.00 - $15.00 per square foot. It depends on many factors: size, location, accessibility, complexity, who supplies what materials, number of devices and light fixtures, gas or electric appliances, generator, pools, spas, etc.