in the Zerynth pinmap (IO view) of the Huzzah32 you can see that several pins have the ADC label; those marked are the Zerynth Supported ADC channels.
You can call the analogWrite method on (A2, A3, A4, D33.ADC, D34.ADC); D25 and D26 pins are marked as DAC (Digital-to-Analog converter) even if in the board serigraphy are called A0 and A1.
Note: before you can use the analogWrite method you have to define the pin as input through the pinMode(pin, INPUT) method (where pin must be one of A2, A3, A4, D33, D34).
To use each Zerynth Supported device always refer to Zerynth Pinmap.
Let me know if this can help you