First:

I note that changing the analogWriteFrequency, at times, changes the pwm value (as previously written by analogWrite) to max (e.g., 255) value. Perhaps when the analogWriteFrequency value is changed too much at a time?

After changing the analogWriteFrequency, I reset the pwm values for all channels.

Second:

Am I correct that using pins 3,4 for pwm means that I cannot use Timer1 for some other purpose?

Third:

When using OctoWS2811 which timers are available for other purposes?

thank you,

Richard