A couple things to note.
1.Silk Air is owned by SQ but you get NO points on it
2. You can connect airside in India without Visa but I would not recommend it as if there is a problem with the connection you can not get a visa at the airport and if you decide to spend a day in DEL you have a problem. Indian visas take a while to get issued here in Canada, my daughter got one in BKK and it took several days and two visits...
3. "Royal" Nepal Airlines has an interesting safety record and methods
http://news.bbc.co.uk/2/hi/south_asia/6979292.stm