Other than Cessna's 206, on account of rear doors not opening with (full?) flaps
FAR 25 required ditching provision.
https://www.law.cornell.edu/cfr/text/14/25.801
FAR 23 on the other hand not nesasserily, depends on the level of aircraft
§ 23.2315 Means of egress and emergency exits.(a) With the cabin configured for takeoff or landing, the airplane is designed to:
(1) Facilitate rapid and safe evacuation of the airplane in conditions likely to occur following an emergency landing, excluding ditching for level 1, level 2, and single-engine level 3 airplanes.
(2) Have means of egress (openings, exits, or emergency exits), that can be readily located and opened from the inside and outside. The means of opening must be simple and obvious and marked inside and outside the airplane.
(3) Have easy access to emergency exits when present.
(b) Airplanes approved for aerobatics must have a means to egress the airplane in flight.
Level of aircraft requirement.
§ 23.2005 Certification of normal category airplanes.
(a) Certification in the normal category applies to airplanes with a passenger-seating configuration of 19 or less and a maximum certificated takeoff weight of 19,000 pounds or less.
(b) Airplane certification levels are:
(1) Level 1—for airplanes with a maximum seating configuration of 0 to 1 passengers.
(2) Level 2—for airplanes with a maximum seating configuration of 2 to 6 passengers.
(3) Level 3—for airplanes with a maximum seating configuration of 7 to 9 passengers.
(4) Level 4—for airplanes with a maximum seating configuration of 10 to 19 passengers.
So only need to address ditching for level 4, ten or more pax.