I don't think it really matters if it's a friend or not as long as they are good and you are pleased with your previous work. But I DO think it matters that your FI doesn't get along with her. The thing is, is that she's going to be around both of yall the entire time, and you want your FI to have a wonderful and memorable wedding day too. As much as it's our day, it's a little bit theirs too. Lol