Changing your name simply wasn't, and still isn't, such a big deal in Sweden. Before 1900 there wasn't even any official procedure, you simply told people what wanted to be called, and most people would take it for granted that everybody adapted their names according to the situation.
In your case Anders might very well have called himself by his patronymic name Andersson on some occasions and Wistrand on others. Both would have been correct, if his father was called Anders he would indeed have been Anders' son = Andersson.
On the other hand I don´t think Andreas' wife was ever actually called Mrs. Andreas Andersson Wistrand. To a swede, the English manner og calling a wife by her husband's first name still sounds odd and a bit offensive. She might have used a surname, but odds are she was known by he first and patronymic names. Before 1900 she would probably not have used Wistrand while her husband was alive, but might call herself Widow Wistrand after his death.