re: The Galaxy does not sit still
I would think that most of our stellar siblings would be in the same orbital plane. Some a little closer to the galactic center and some a little farther (Kind of like our planets orbiting the Sun)
As they orbit the Sun should occasionally pass up or be passed up by one of its siblings (Just like the planets do).
Seeing there has been only around 18 orbits since the Sun was born, I don’t think it has happened often.