I have often had mechanics flying as a passenger volunteer to assist in a repair at a out station. Many out stations use contract maintenance and a mechanic who actually works for that airline is normally better qualified to work on the airframe.
Some smaller and low cost airlines contract nearly all their maintenance.
Crew duty limits used to have a lot more leeway then today. The new FAA rules that went into effect about 3 years ago have hard limits that can't be exceeded under any circumstance.
The hotel situation sounds like owners trying to take advantage of the weather in the NE as well as the mechanical situation.