Termination resistors are used when cable reflections are expected.
High switch frequencies and long cables.
If your teensy is 30cm away from the first IC, there is no need for that.
And the LED chips are not boosting the signal, they are buffering the signal.
You only drive the first IC. That IC buffers the data, and passes it on to the next one.
Try two small mosfets or two NPN transistors with 1k base resistors.
Takes 10 minutes to hook that up on a breadboard.
Make sure you reverse your output pin code.
Leo..