The Lost Boys seem to prey on mostly young people out on the boardwalk. Young people tend to be out very late partying, and would probably not be missed until the next day ... maybe not even until a few days later.
Most of them seem to be young adults, who likely live alone and wouldn't be missed for weeks.
When David sucker-punches Michael before their fight, he's deliberately trying to piss him off, so he can trigger his bloodlust.
Max momentarily freaks out when he sees his own reflection. It's because he normally can't see it, as he only has a reflection when invited into someone's home.
When Max returns home one night, the Lost Boys throw a bat kite at him. It sure does seem like something mischievous boys would do to prank their father. Plus, it hints at a good-humored acknowledgement that they are all vampires because of him.
Max keeps mixing up the idiom that it's bad luck to see the bride before the wedding, saying it's bad luck to see the food before the meal. Meals and brides are often the same thing to vampires.
In The Tribe, Chris and Nicole's aunt doesn't give them many rules, but tells them she'll kick them out if all they do is party, flipping out at them at the end of the film because she thinks that's what they have been doing. The first impression is that she's unreasonably strict (Chris is over 18, and Nicole's guardian), but the police station has a wall literally covered in missing person posters, most of them the age of Chris and Nicole. She's not being strict, she's fully aware that in the town, a lot of teenagers have gone to parties but never returned home.
Max owns a video store, possibly the only one in town. You have to sign up for the service and leave your name and address. That way, he will never have a problem finding young adults to adopt.
When Sam forces a mirror into Max's face when trying to figure out if he's a vampire, he has a reflection.
It's possible that inviting him in made the family unable to detect any of the signs, as part of "rendering you powerless."
Then why doesn't Nanook detect him as a vampire beforehand, when the dog first meets with Max?
It renders the house powerless. Including its pets.
Why doesn't any of this apply to Michael, given that it's his house?
Simple answer: it's already his house. No one has ever invited him in. He already lives there.
Max chortles as Michael appears to attack him. He knows Michael has about as much chance of hurting him as a four-year-old has of hurting a UFC Champion, but he's also about to give his potential new stepson a fatherly little lesson about knowing his place.
Bonus when you recall the scene at Max's video store, and how the boys instantly back away when ordered. It seems pretty clear that Max does not tolerate ANY backtalk from his "boys."
One thing that was never explained in The Thirst. If Peter is the Alpha Vampire, meaning he's the very first of his kind, but you have to drink a vampire's blood or be bitten to become a vampire, then who the hell turned him?! For that matter, HOW?
Various media usually depict the original vampire as either having been born that way (a mutant or a remnant of an older species) or having gotten their powers from black magic (being cursed or making a Deal with the Devil).
