This is a timely thread! I've also preordered a few T2s that I want to use with neopixels. Currently I'm using an Arduino Uno with the Adafruit library. I've read up on the posted links and I may be able to help with the firmware development, though I haven't done stuff this low-level since college (after all, JS support was what attracted me to Tessel in the first place ).
I'm concerned about this comment of yours from another thread: "That is so that you can animate several frames without having to jump back and forth between the C and JS (which is too slow for smooth animations)."
Is this still true for the T2? I would like to control the pixels on a per-frame basis from the JS. I don't want the firmware to handle animations/timing, just pass it a full frame and it draws that as fast as possible, using an event loop and clock on my end to control the state of the animation.
Do you think this is feasible? Thanks!