... from the other side of a glass door
it is forbidden for the inbound & outbound crews to meet
in some places. So you can see the outbound crew at the departure gate as you follow the passengers into arrivals. Just one example.
As to 747 turnaround times; 1:30 would be pretty tight if you need to take on a hefty fuel load - the fuelling can take about an hour; think about it: deplane the pax ~15 minutes, cleaning about 15 minutes alongside de/re-catering maybe 20 minutes, all before cabin checks of 10 minutes before boarding of about 40 minutes. Add those up (15+20+10+40) = 85 minutes.
So about 1:30 for an en-route transit, eg in Singapore in LHR-SIN-SYD is about right. When however, you are talking about the ultimate destination before beginning the return Longhaul journey, then to allow for schedule regularity, then usually 2 hours upwards will be built into the schedules .
On occasion sub 1:30 is easily achieved (eg LHR-Bahrain-Doha) where limited fuel is required, same cabin crew, limited pax changes, no catering etc.
Downroute hotels: it is not always the case that crews stay in the same hotel at a location, although often they do and naturally they can meet up as frequently there are popular haunts, and airline crews are easily spotted!