These Death Registrations may show that the Informant was a relative and give their address. But before you even do anything about getting copies of these certficates you should check the obituaries in the Vancouver Sun and the Province for about 2 weeks afer their death dates. You may find offspring that way. And then you can try the BC Directories for those names and hopefully find names of spouses and addresses and phone numbers, and then check the Directories in subsequent years for more up to date information. Also you can take these latter names and have a look at the BC Archives site to see if perhaps they, in turn, have died. etc. etc.