Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Auto Add Post Effect
HAIR_PREFS_SETUP_AUTOVPParameter: Auto Link Object
HAIR_PREFS_SETUP_AUTO_LINKParameter: Auto Add Material
HAIR_PREFS_SETUP_AUTO_MATERIALParameter: Hair as Child
HAIR_PREFS_SETUP_TOCHILDParameter: Highlighting
HAIR_PREFS_HIGHLIGHTINGParameter: Show Unrooted
HAIR_PREFS_UNROOTEDParameter: Cursor
HAIR_PREFS_SHOW_CURSORParameter: Object Modify Undo
HAIR_PREFS_OBJECT_UNDOParameter: Dynamics Undo
HAIR_PREFS_DYNAMICS_UNDOParameter: Default Preview
HAIR_PREFS_PREVIEWParameter: Custom
HAIR_PREFS_CUSTOMPREVIEW