Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Strength
ID_CA_MORPH_DEFORMER_OBJECT_STRENGTH
Parameter: Morph
ID_CA_MORPH_DEFORMER_OBJECT_TAG
Parameter: Apply Base Pose
ID_CA_MORPH_DEFORMER_OBJECT_APPLY_BASEPOSE