TI launchpads can be bought direct from TI. I don't have a link handy.
As for the ESP8266, Adafruit sells a board called the HUZZAH ESP8266.
For both, the best resource in my opinion for environment set up/build system is platformio (platformio.org). It exposes an Arduino-style API for both boards, so basically the arduino docs will get you 95% of the way there, and the community sourced libraries in platformio will get you the rest of the way.
