Are girls lacrosse Stick heads interchangeable if they're different brands?
Answer Same as with the mens sticks usually yes. Debeer has a new line that has an offset. Those sticks and heads need to be matched. http://www.simplylacrosse.com/debeer-head-with-a-harrow-shaftare-they-compatible-and-tos.html
but most others do not. Always to be sure ask your retailer or manufacturer for specific info regarding your stick.