Divorcing one wife by saying her name but the another wife's name came to mind

Q: If a person has 2 wives and he, intending to divorce one says her name then explicit words of divorce like "Maryam I....(explicit words)" but at the time of sayings the words he has his other wife who he didn't want to divorce come to his mind.

Does it mean he accidentally gave divorce to the other wife (named Zainab) which he didn't intend to?

Woman going into her backyard without a scarf

Q: When I go outside to my back garden to throw something in the trashbin or do quick task, sometimes I don’t wear a headscarf or I wear it loosely. It can be inconvenient to have to put on proper hijab if I’m only going to go out for a few seconds. However, I usually peek out to see if the neighbours opposite our house have their lights on in their window and/or if they are actually looking out of the window at the time of me going to the garden. If I can see them then I will cover myself, otherwise I won’t. If a couple of strands of hair are visible then I don’t see it as an issue as they would not be able to see my hair all the way from their window. Is what I’m doing permissible?