What restrictions apply to private residences, farm buildings, and other buildings? Will landowners lose any use or development rights?

No restrictions to private lands may be applied under the Wild & Scenic Rivers Act. Comprehensive river management plans may establish goals for new construction consistent with classification. There is a wide range of uses compatible with these classifications so long as the overall values and character of the river corridor is maintained. Any effect on private lands would be through state or local zoning. Federal acquisition of lands or development rights would require landowner compensation.

Source
Interagency Wild & Scenic Rivers Council