As you probably know, where I live there is a long and still-very-much-alive tradition of intense musical expression at funerals. So this doesn't seem at all weird to me...

You won't have a problem determining "WHO is going to be singing along" ~ even at an actual funeral, there is only one dead person along with plenty of surviving loved ones and other individuals. And this isn't even a funeral, it's a party at a funeral home.

Have fun!