My god, you lack awareness. You so obviously like her and are trying the good friend back door gambit should she ever break up with her fiancee. You would NEVER even consider this if you had a girlfriend.
Hahaha, dude, there's no 'good friend backdoor gambit' when you're friend zoned. That's the only way the fiancée would even allow us to be friends, I'm sure.
Totally okay with it, but that's why I asked here so I could maintain the friendship and not screw shit up.