Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Include Children
OUTLINEITAG_INCCHILDRENParameter: Allow Lines
OUTLINEITAG_TOONALLOWEDParameter: Allow Shading
OUTLINEITAG_SHADERALLOWEDParameter: Render Culling
OUTLINEITAG_MODEParameter: Style Tags
OUTLINEITAG_TAGLIST