Can a Custom Pencil Brush include Transparency?

[Blighty]

(05-21-2019, 11:32 PM)pha3z Wrote: I can have:
a) An RGB brush with anti-aliased edges and transparency
b) An RGB pencil without anti-aliased edges and without transparency.

Is this correct?

No, that is not correct.
You can have
An RGB brush with anti-aliased edges with or without transparency
An RGB pencil without anti-aliased edges with or without transparency

This difference is the transition from the transparent to the non-transparent areas.