Personally, I don't think human remains will make it across, nor much of anything else organic. If water can get to it, then so can the millions of little critters that will eat it...and in 3 years....not a lot left. As for the other debris, to be honest, I don't think it will be a huge problem. I think we'll have more than enough people to help clean it off of shores and beaches, and more than enough people willing to do what is needed to help each item's former owner to find some type of closure. I see a website taking over this...Because those were some very old villages and towns that got wiped out...a lot of heritage, and a lot of ancestry. If you know anything about Japanese culture, you know how important that is. I would like to think at least SOME of it is salvageable...if not totally pristine.
I also expect to, in 5-10 years, see some of that stuff floating in the Long Island sound...almost everything ever dropped in the Ocean...ANYWHERE, seems to end up there.