I GOT BOTH THE LIS3DH AND THE TCS34725 TO WORK ON I2C!!!!!!!!
I realized that the LIS3DH has an example of two accelerometers on I2C. I took that example and altered it for the TCS34725. That's another problem solved! This means that I can finish soldering and be sure of how I'm doing it.
I started looking at the Neopixels again. I narrowed it down that when function1 or function2 are called, that's when the data starts printing slow. I don't know why. But I feel a little better that I can tell where in the sketch it's going wonky.
If you are looking for a summary for my Masters thesis, it is here.