Congratulations!

Afraid I can't answer most of your questions. But from Duke's excellent list, I'll second the notion that Cathay Pacific business class is superb in terms of both seats and service, plus Hong Kong and its lounges make for a nice transit point (or even a city to visit if you have a very long layover).

You make a good point about flying on Singapore Air requiring an extra stop, though if you view your flights as part of your honeymoon it has probably the nicest business class seat around, as well as great service and a very nice airport (and if you have time to visit, an easy and pleasant city) to transit through.

Etihad is also very good, but transiting through Abu Dhabi reportedly can be a real pain.

Unfortunately, I don't know for sure about the quality of the business class on the shorter hops from any of these airlines' home airports to BOM.

Steer clear of BA, LH and any US carriers, as their seats and/or service are inferior to other options. Plus, FRA (for LH) can be a real nightmare to transit through.