Though I have a seaplane rating I've never thought it would be that much use when ditching a land plane. If the worst happened to me I hope I would at the minimum sqawk 7700, contact ATC or D&D and prepare for impact and evacuation. I think a good pre-flight passenger briefing is invaluable so that everyone has some idea what to expect and what they can usefully do. As for lining up into wind or along the waves - I suspect when you get that low the conditions will be changing too quickly.