Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Color
ID_LAYER_COLOR
Parameter: Solo Mode
ID_LAYER_SOLO
Parameter: Viewport Visibility
ID_LAYER_VIEW
Parameter: Renderer Visibility
ID_LAYER_RENDER
Parameter: Manager Visibility
ID_LAYER_MANAGER
Parameter: Animation
ID_LAYER_ANIMATION
Parameter: Generators
ID_LAYER_GENERATORS
Parameter: Deformers
ID_LAYER_DEFORMERS
Parameter: Expressions
ID_LAYER_EXPRESSIONS
Parameter: Locked
ID_LAYER_LOCKED
Parameter: XRef
ID_LAYER_XREF