If this is what you refer to as family registry...then,I didnt understand you.
Married and singles applicants needs to list out their family members in form IMM 5406....if this is what you refer to as family registry...my apologies.
You need to list all of them out in the form....its not only singles but for married pple as well
if they are more than the specified columns on the form,make an extra sheet to accomodate them.
This is useful for future purposes as it will be easier for you to sponsor them.
Cheers!