Feedback sought on audio output circuit for Teensy 3.2
Am guessing that Teensy 12-bit DAC output is from the processor directly. Spec sheet says that DAC output Z is 250 ohms, tested with a light load of 3K ohm. So your anti-alias filter has a flaw - those 47 ohm resistors are in series with 250 ohm DAC output Z (I'm assuming that processor's DAC outputs are not externally buffered).

The anti-alias response of your low-pass filter rolls off audio above 536 Hz., not the 5000 Hz that you expect. I would suggest increasing R901 &amp; R902, and decreasing C901 &amp; C902.
The 10 uF coupling capacitor is likely large enough to drive an audio power amplifier input, which is usually many kilo-ohms. Since you're driving little speakers, the high-pass corner frequency should be adequate. Ensure that your power amp does have relatively high (>10K) input Z. Power-amp input resistance is in parallel with C901 &amp; C902. Power amp input resistance combines with (ADC output Z + R901) to form a voltage-divider, attenuating audio in the pass-band, so don't make R901 too large.