No. Some work needs a permit or a licensed electrician under local rules, and each provider decides what they offer. Describe the job when you book so your provider can tell you whether it is something they take on.

You do not need to. Your provider will switch off the circuit they are working on. Keeping the area in front of the breaker panel clear helps.

Your provider's published rate, the number of items, how accessible they are and how long a fault takes to trace. Your provider confirms the price with you before the work starts.