It depends on which library you use.
If you use WS2812Serial or OctoWS2811, then yes. Those are non-blocking and do not interfere with audio processing.
If you use Adafruit_NeoPixel, then no. That library blocks interrupts. It can only drive a very short strip before it blocks too much and disrupts audio. Then good news is WS2812Serial implements API compatibility with Adafruit_NeoPixel, so if you've already written code using Adafruit's blocking library, usually it's pretty easy to switch to non-blocking WS2812Serial.
If you use FastLED, then the answer depends on which of FastLED's drivers your code uses. The default WS2812 driver is similar to Adafruit's library. But FastLED has drivers which use WS2812Serial and OctoWS2811. So if you use those drivers, you can have the audio friendly non-blocking behavior and also leverage all the fancy color and rendering features of FastLED.
No matter what you do in software, you should consider the hardware issue of ground loop noise from the beginning. If you power the LEDs from an earth grounded power supply, and you transmit audio to an amplifier or other gear which is earth grounded, you'll almost certainly get ground loop noise. It's a general audio issue, not specific to Teensy or NeoPixel, and you can find lots of info online about audio ground loop noise. While planning grounding is best from the start, if you do run into problems where you hear funny noises corresponding to changes on the LEDs, sometimes this product can help.
https://www.pjrc.com/store/audio_ground_isolator.html