I'm pretty sure that being manly and feminine don't have to do much with sexuality. Manly seems to define a more macho/tough mindset where is feminine is more along the lines of being sensitive (Not that people can't be tough and sensitive mind you).
As for Spinelli, having a crush is something all gender go through whether sensitive or macho, so I can't really say that crushing on a guy contradicts her tomboy attitude.
Even then, if we were to go by your definition, she would count as a tomboy still:
1. That crush you bring up, she displays the symptoms of a crush, but she never allows for one moment of being satisfied with that feeling nor does she display any happiness towards her crush.
2. She actually takes offensive towards being refered to as a girl even if it's not being used in a negative way.