I've been watching for a while and think I can answer some of the questions raised here about the show.
When they did the first show about the bar, all four kids came to Tia and suggested it. However, around the time that the show aired, I remember seeing that the twins were going to be handling the day-to-day operations more while the girls stayed on to help out with the rescue. The division of labor seems to be a little less black and white than that, but as the girls are in almost every episode and the twins only show up less, I'd guess this may be how its working out.
I believe Perry was addicted to heroin.
The house by the river was supposed to be the twins home. It was destroyed after a hurricane (Gustav??). After Chong died, the show did an episode where the Marines who helped with the original build out of the house came back to clean up and restore it. Tia mentioned that the plan was to use it as a home for senior dogs. I'm not sure if this has already happened and just hasn't been shown yet.
The show has been very helpful in getting lots of volunteers to their doors. I follow them on FB and Tia mentioned that she has moved out of the city and is now living on a couple of acres of land where she is keeping all of the hounds that the shelter has taken in. Evidently, the hounds tend to bray and need room to run so they moved them out of the the shelter. She posted a funny story about chasing a couple of hounds that escaped on Christmas Day.
My recollection is that there has never been a specific how-to for aggressive dogs, but Tia has talked generally about some of the methods they use when dealing with dogs they aren't sure of (using two leads instead of one, the use of treats and food, etc) I remember specifically this being discussed in the rescue where Mondo's friend took in a female dog and her pups and then called because the dog was too aggressive to handle. The one shortcoming of these shows is that none of them really give advice on how people that see the same issues can approach them. I'd guess that is to limit liability for the show and the producers.