Well, went out yesterday after lunch, removed hose bib and connected straight to schedule 40 tee, started warming up poly with torch. Pipe eventually split from pressure/heat, figured may as well connect straight to poly. Cut poly 6 inches lower, chipped away at ice/slush. Opened all valves, started compressor and water was actually coming out of sprinklers, with not great force. Quickly diminished to a trickle, then nothing. I figured ice/slush got pushed into valves or just before them and stopped water flow. Called it a day, will have above freezing temps next week with rain, will try again then.
Client did mention that he's moving this winter to a bigger property and will require irrigation, want to make sure he's happy