No, this is not overstocked

It should be fine

Actually, you can make it 4 or 5 Cherry Barbs as they like to be in groups. I presume cories grow to about 2 inches? Also, do cories eat algae? Because I see you've eliminated the algae eater. Once you start getting a lot of algae and you won't have an algae eater, you'll probably want to get one to clean the algae. And it will be difficult if your tank will be already fully stocked. Anyway, do cories eat algae? (Sorry, I really know very little about these fish.)