Alhamdulillah Engine started on the first try. Sound was little louder than normal because of new pistons, no strange noises though. We gave each other high fives.
Ran the engine for 3 hours at the workshop, then took it for the test drive..
After 20 minutes or so, we turned the AC on to check, strange clicking noise started, we first thought it was from the engine. We pulled the car over to check, the engine was normal. We turned the AC off, after few minutes the noise went away, as soon we turned the AC back on, the noise came back. The mechanic checked it, this was somehow related to AC. What a relief. The mechanic will check it again Monday and will try to rectify it.
I brought the car back home, then again went for a drive, no issues other than AC related noise.
I would be able to share the mileage and performance in the coming day. I am really happy with the result so far.