Is there a discernible difference in taste between aeropress and chemex / pour-over?
I'm guessing that there will be some difference in taste, depending mostly on the amount of time the water spends with the coffee grounds. Depending on how long you let the water sit with the grounds before the press part of the Aeropress will increase the bitterness of the coffee you pour off and drink.  Similarly, the more water you pour over your grounds in the Chemex, the more bitter your coffee will be.

If you only use one cup of water in both methods, and don't let the Aeropress steep very long, the more similar the taste of the cups of coffee will be.  But if you pour a second and third cup of water through the Chemex without changing the grounds, the third cup will be significantly more bitter than the first one.  Similarly, if you let the water in the Aeropress sit in the water for 5 minutes before pressing the grounds down, your coffee will be more bitter than one that sat for only 1 minute.