What I have a hard time with is #4 above. Sometimes I want to set someone up with someone else, but I know that one is Frumer than the other, so I’m not sure if it’s a problem to set them up. Usually, one person is Frumer than the other, and when you’re “older”, most people say that you shouldn’t not go out with someone who is more modern than you, which would imply that maybe it is okay to set someone up with someone more modern than them.
But the question is at what point is it a problem? Clearly you shouldn’t set someone up with someone whom you feel will have a negative effect on them ruchnius-wise. But how would one define that? Also, a lot of people would probably say that it is more important to just get married, no matter who you marry.
I had this issue recently when I was debating whether or not to suggest a girl who wears short skirts to a certain boy. I did anyhow, and it turned out he had already gone out with her, so it didn’t matter anyhow.