All characters on the account have the same privileges as the character that bought the house. They can do everything the character that bought the house can except for one thing: abandon it. Only the character that bought the house can abandon it, and if they are deleted the house is released to be resold. Not even sure you can add their name to the permissions list to restrict them. But every character gets the same discounts, rights, privileges, etc.
"Everyone's got one. Better to be a smart one than a dumb one." - me
"It's people like you that [I]think[/I] you know everything that give those of us that [I]do[/I] a bad name." - me
"Eat, drink, and be Merry, 'cause Pippin was a fool of a Took."