All I can tell you about red nail polish is the following: I once read a secular book on dating called “How to get married after 35.” The author had this whole really intense shita about how much “hishtadlus” you have to put in, and how everything you do should revolve around hishtadlus to get married.
She had a section on dress and appearance, and as you can imagine, she felt that was an important part of hishtadlus – making sure you look your best at all times, in every way. I specifically remember that she wrote that you should NOT wear red polish since you are looking for a guy who is looking for a wife not a zonah. This was coming from someone who was completely secular! When I read that, I realized that red nail polish clearly has connotations that some Frum girls don’t realize.