How would you go about contacting a girl you've never REALLY met? (edited)

[Mr Khan]

This does seem dangerously circuitous. Designate the target girl "T" and her friend "F," and the buddy you initially mentioned "B"

If B is in good contact with F, have B propose a group get-together with you, T, B, and F. Something casual, through which you can meet her in person, then friend her immediately afterwards. It would be odd indeed to come out of the blue like that, mostly through having to explain the connection.

Or you can hide the connection altogether, not explain anything, and just take the dive.