I'd like to be able to use my function keys without needing the "fn" key itself when I'm bootcamp-booted into Windows. Any ideas?

Even if you’ve used the Mac for decades, I suspect you have never fully understood the Fn key. Not helping is the fact that Apple sometimes calls it the Function key, but all Mac keyboards already ...

In the keyboard section of the system preferences there is an option that might help you. I don't have my macbook pro present right now so I don't know exactly what its called.