I don't see what's hard about DIYing your own WS2811 controllers? Their hardware performance might not outdo a $200 controller, but 66 Arduinos sure...
There was a time, not really that long ago, when you had to build your own controllers, sometimes using point to point wiring, too. Then someone came...
I think you're really going to struggle with getting text to look good on icicles that are 8 pixels in height. With that having been said, I believe...