You probably have to strip them. AE's have a fairly heavy topcoat so if you're going to be doing dyeing with Feibings or something that needs to be completely off. Also if you are just going to be using colored polishes to try to achieve antiquing you might run into some problems. It takes a very long time to change the color of shoes using colored polishes only. if you try to do it in a sitting you are mostly going to apply too much and gunk up the shoe not actually antique it.
Ok good, I'm picturing a multi year process, just layers on layers of cream polish of varying shades of brown