I would be very surprised if you could get into trouble for deleting some premades. After all, if you play with them normally and allow them to age, they'll all die sooner or later anyway. San Myshuno has the Landgraab apartments, and they're functional even without the Landgraab family in your game. I imagine it's the same with anything that is named after the Michaelsons in San Sequoia.
Funny that you mention werewolves, @CAPTAIN_NXR7, because that's the one pack where I actually had a problem with special sims not respawning. I can't play with wolf packs in my main save because the leaders are gone, no one is taking over, and the cheats to appoint new leaders don't work.
But since the Michaelsons from San Sequoia don't seem to be important to anything but the lore, which is just text anyway, nothing like that should happen if they disappear.
