Turning her down twice shouldn't affect the other routes at all in a negative way. If the other routes broke off, it's likely something else.I turned her down twice and it broke the routes with others. I don't really know how to explain it better than that, I am not knowledgeable with how the code works.
It's worth noting that you cannot end up with all 5 other main LIs simultaneously. At most, you can have a polycule with 4 of them (Heidi, Athena, Mora, and Sadie), but you have to meet certain requirements.