Aptitude doesn't work to qualify you for High Sword Low Axe. It doesn't give you extra feats, it just lets you apply your existing weapon focus-like feats to the Aptitude weapon. Even if that meant that you count as having the feats for meeting qualifications, which I don't think it does, it still wouldn't work with HSLA because it asks for WF with a whole weapon type, not just that one axe you happen to be wielding right now.