I think girls learn a great deal of halacha while in BY and even in seminary. They have to know what is necessary for the lives they are living at that time. I mean how have they been keeping Shabbos and kashrus up until now. I mean my daughter had a test in 10th or 11th grade on the 39 melachos and she had to know tons of stuff by heart. Does she need to take a whole new class on hilchos Shabbos before she gets married?
When she gets married and starts getting involved in new situations that she never came across before, then she should not hesitate to ask questions about them to find out the proper way to behave in these new situations. You will find classes for married women in things like Hilchos Shabbos and maybe even kashrus in various neighborhoods, but perhaps it is something that the husband and wife can learn together on a case-by-case basis when she has something new she is not sure about. Of course, as a married woman, she has a whole new set of halachos to learn about for taharas hamishpacha.
More enriching for a woman is to learn hashkafa and mussar. These help shape her attitudes about the things she is involved with until the time she gets married and hopefully a girl who likes to learn these kinds of things before she gets married will continue on afterwards. Again, this can be learned between the husband and wife and will help keep them on the same page hashkafically (I hope).
Depending on what exactly you want your future wife’s focus to be, you could tell a shadchan that you are looking for someone who is into spiritual growth and sees learning as being an important part of her life at the present time and wants to continue after she gets married.