Yes. The add-on is designed for both Cycles and Eevee. Cycles usually provides more realistic reflections and subsurface detail, while Eevee is useful for faster previews.

Yes. Grass and Twigs support custom object collections. Select the collection in the effect settings, then adjust the amount, size, length, and distribution controls.

Yes. The effects follow the character mesh during animation. For the most stable result, keep the character topology unchanged after creating masks or binding a guide curve.