These places have large rooms and pretty good soundproofing and not much going on at night. They have these cool stretch hearses that can load the DJ’s stuff in. There are these big long boxes that would be great bars. Those that are empty could be filled with ice and be really great coolers.
Now while your jaw has already dropped, companies have to make every moment be profitable, so why not?
Remember the folks who are there won’t mind the loud music or rowdy behavior.
If the property owners time it out right, there will be time to get the drunken mob out, clean up, put the chairs back in and start all over again with the maudlin act of bereavement for those who have passed.
If it becomes a Goth party, things could get out-of-hand, but while the family is at home mourning the deceased, think about the party they are going out with.
After that is just a hole in the ground with a party for the worms.