“I don’t understand that Gemara at all”
What don’t you understand about it?
You are correct for distinguishing between a nisayon and an issur. In all of our above cases, we were talking about nisyonos and not issurim.
However, I also don’t think the case in the Gemara (as I understand it) is similar to our cases. In the case of the Gemara, it is referring to the issur of histaklus which can bring someone to a nisayon, but is not necessarily a nisayon for the particular person.
I have heard of a teshuva from Rav Moshe Feinsten regarding a man who has to sit next to or near untzniusly dressed women on the way to work. He poskened that it was okay based on the above Gemara. I have not seen the teshuva inside so perhaps I am mistaken (maybe someone here who is familiar with it can provide the link), but my impression was that the reason he says it’s okay is because it’s not davka a nisayon for the person. And that is my impression of the Gemara as well.
But if I’m mistaken about either the Teshuva or the Gemara and someone has sources proving otherwise, please let me know.
In our cases, we seem to be talking about things that are nisyonos for the people involved. If something is a serious nisayon for someone and they are seriously concerned about it, I am not sure that “leica darka achrina” would apply. I would imagine that this would depend on the extent to which they are concerned vs. the necessity of doing the action.
In LB’s case, one factor seemed to be the fact that she didn’t seem to think it was so necessary to do anything. If she had, I think she could have found another solution so I’m not sure that “leika darka achrina” applies.