Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Freeze
FREEZE_FREEZEParameter: Variation
FREEZE_VARParameter: Over Age
FREEZE_OVERAGEParameter: Age Gradient
FREEZE_AGEGRADParameter: On
IN_FREEZE_ONParameter: Animation Time
IN_FREEZE_ATIME