Hi,

Two part answer:
1. PhoneGap (and similar solution) basically expose a limited set of apis to Javascript (basically translate the original Java / Objective C hook into Javascript and vice versa). I'm not sure PhoneGap will support the API's you need - however Nativescript should (it's a javascript library, happy to connect you to the right people if you want to use it).
2. Performance limitations of PhoneGap etc. is divided between rendering (which shouldn't really be an issue) and the fact that Javascript just runs slower than native code. If you do require heavy computation I'd suggest sending it over to a python server (over internet / wifi) but I suspect Javascript should be able to handle most of the computation.