We love Kaitlyn because she can keep it at the full name to be professional but she can also shorten it up to Katie if she'd like a nickname. We will never use Kate, unless it's what she ends up preferring when she's older.
As for her middle name, it was my grandmother's middle name. I've always had a special bond with this grandma, down to the fact that I got married on her birthday and then she passed away on my birthday. So her middle name is extra special to me.