Your chance of mixing tangs and have them get along increase if they have different body shapes. No absolutes as these animals all have their own personalities.
Bailey52.....Yellow tangs get quite large which is why they cannnot live through adulthood in your tank. In my opinion, success is having the same fish for years...not days, weeks, months., or one year. If you want to keep a yellow through adulthood...he will not be happy in a 90 and will most likely die from stress once he feels cramped.
Can you put a small tang in your tank...yes...will he/she live through adulthood...not likely. JMO