Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Scene
FP_GROUP_SCENE_LINK
Parameter: Link to Default Scene
FP_GROUP_SCENE_LINK_TO_DEFAULT
Parameter: Draw Mode
FP_GROUP_DRAW_PARTICLES_MODE
Parameter: Draw Radius
FP_GROUP_DRAW_PARTICLES_RADIUS
Parameter: Size
FP_GROUP_DRAW_PARTICLES_SIZE
Parameter: Override Mode (Display)
FP_GROUP_COLOR_OVERRIDE_MODE
Parameter: Override Color (Display)
FP_GROUP_COLOR_OVERRIDE_CONSTANT