Are people going to put their own ideas. Could be that you need a section suggesting what possessions some folks have just to jog peoples memory. E.G. Where are your bank accounts,where is your will, who actualy owns the house (obvious but it means you have made a start with the easy one, a lot of folks will say Nationwide Building Society for the next 8 years or something), any investments, stocks, shares, saving plans with Nationwide Building Society. Have you any loans? I cannot imagine anything worse than a grief stricken spouse getting a visit from bailifs(?) because the deceased had not told his partner he had taken out a loan. And credit cards (?).
I think I might be redesigning your site, SORRY. But you did say