I'll use Medaglia D'Oro or Cafe Bustelo instant coffee. Via's are too costly for me. Cafe Bustelo now comes in the small tubes similar to Via.

I have an msr liquid fuel stove, but haven't used it in 10+ years and then only used it in the winter. I usually use my pocket rocket or a homemade alcohol stove.

I like Don Newcombs idea. Also, you could just not stay in the shelters and go back to the tent on the ground.

I've used esbit on a homemade 'stove' & windscreen. It worked great. Sometimes you can use a tablet for 2 cycles. But they smell extremely bad and they leave a sticky mess on your pot.

I doubt you can bring them on a plane, maybe if you checked your bag. That should be easy enough to find out.