Apparently mobile phone coverage is good for almost all the Everest Base Camp route. Don't know about Annapurna. However, I would expect leaders of commercial treks to carry Sat Phones, which should work almost anywhere. Hopefully, you will hear something soon.
Very sad news. When I went over the pass circa 1982 there were very few people about. I think it was only the second year that side of Annapurna had been open to trekkers. At least communications and rescue facilities have improved since then. In 1982 there were no phones or helicopters.
The flame size was the same, within one run comparing BruPot to MSR, except in the one test where it clearly says it wasn't! As I was using a remote canister stove I had problems weighing the cylinder accurately without removing the pipe. Of course this meant I had to turn the stove off, so the flame size when I turned it back on wasn't necessarily exactly the same.