Good story! Thank you for sharing!

Regarding the absolute universal charger.
They do exist or can be easily made (LM317 IC 3-40V in, 1.5V out + that AA step-up charger). The only problem (IMHO) is with the connectors for every phone. There are way too many different models. So, along with some of the most popular connectors, you have to carry some tools, wires, and skills to improvise.

BTW, EDC playing cards eBay