I can't nswer all the questions.
RJ does not have any in town check in facilities like CX does. RJ has one in Amman though its not be in the absolute centre and going straight to the airport is often more convenient.
I don't recall anything odd about RJ check in at HKG. To be honest I can't remember which lounge RJ uses. It could have been the CX one. I just used the BA one using my BA card.
I am not an expert of seats on planes. Maybe others can answer that one.
I am not sure if it was RJ back from DEL or HKG but when I had a 6-7 hour layover in AMM onthe way back RJ offered me a room at the Golden Tulip airport hotel at their expense. The hotel's not that great but I did get 3 hours sleep in a proper bed plus breakfast.