If a friend changes alias will he still appear in my friends list under the new alias or will he appear under his old alias for a while?

When an alias is changed, the friend will disappear from your Friends list.
However, we will keep any notes that you have made about your friend, if you then re-add your friend (With the new Alias) to your Friends list, the previous notes will auto re-appear

More Questions and Answers you can see when clicking Members --> Friends List on our home page.