Using WS2812s & IR on TeensyLC:
I have a project that uses an IR receiver and a Teensy 3.1 to drive a strip of 300+ WS2812s. It works with a single strip even though the data out pin is only 3.3V. But it will not drive 2 strips in parallel off the same data pis as a 5V arduino will.
However, when I build the final setup for installation I want to use the TeensyLC since it has a 5V level shifter on output pin 17 so that the data pin will send out data at 5V.
The Teensy 3.1 works with WS2812s & IR interrupts flawlessly.
Does anyone know if FastLED will support the use of the interrupts and WS2812s like the Teensy 3.1 does?
I’m thinking that you want a Clock “FanOut” Buffer/Driver. This will take one input and copy it to 9 output pins.
Or you could use this beast that lets you enable / disable the output lines with I2C
http://www.ti.com/lit/ds/symlink/cdc319.pdf
Or to keep it simple just use a multi gate AND Gate, common input 1 with your signal and tie all the other pins HI and let the gate do the driving for you. Either way you get to play with hardware 
All very good suggestions.
The install will only have 1 strip to be driven. But the prototype setup has very short wires. The multiple strip mention was only to indicate how tenuous the operation is. I’m not sure how the longer wires of the install will affect the marginal operation of the single strip. The Teensy outputs are 3.3V max. But the WS2812s spec as requiring 3.4V on the data input. If the TeensyLC doesn’t work well with the IR interrupts, I’ll use a level translator to drive the ws2812 data line. I have a TXB0104 on the way.
Another project will need to drive 16 strips independently. I’ll most likely use a pair of TXB0108s to drive them.
I just received the TeensyLC and loaded code onto it that has been running perfectly on the Teensy3.1 and it behaves exactly the same. The TeensyLC does support the use of interrupts for the IR receiver and WS2812s.
So I can take advantage of the pin 17 5V output to drive the WS2812s.