Eyefuson ji,

No need to worry about visa in HK. But, I strongly suggest that you should fly Dragon [great service, on time flight] rather than Nepal Airlines [Personally, I would not fly Nepal Airlines even they provide me free ticket]. I don't know how much you paid for Cathy+Nepal Airlines, but I just booked $1,237 (Economy "K" class, Cathy+Dragon) and I'm going to upgrade it to Business Class like I did last February. 'K' class has flexible departure/arrival dates so you can adjust your travel dates as you want. I'm frequent flyer with Cathy and this time I plan to go to Nepal in March 6th.

No, you don't have to stop-over with Dragon in Dhaka (I have never done it before, may be it was my good luck).

I advise you to apply for 'Asia Miles' membership (at www.cathaypacific.com/cpa/en_INTL/homepage) so that you will be eligible to get other extra facilities. If you haven't booked your ticket yet, then provide your membership number to your travel agent or you can turn-in at the check-in desk before you depart.   

Eyefuson ji, do you know what is maximum months or days a US Green Holder can stay outside of US? I just heard that USCIS is modifying GC holder's maximum stay out of US from 6 to 3 months. I like to verify if this is true.

Eyefusion ji, what is your departure/arrival date?

Have a great flight to Nepal.... ...!