I went through the process 3 years ago but it may well have changed since. For what it's worth, I had a ~45 minute interview with the 737 Chief Pilot, the Pilot Manager (I think) who has since left and someone from HR. There were no technical questions, just the normal tell us about yourself and why do you want to join us.
The Sim assessment was with CTC on a 737-400. It was the usual profile of SID, general handling, STAR and ILS as both PF and PNF.
Hopefully someone else has more up-to-date info for you....