I agree that the yellow flowers are not Melampodium based on that description. The only thing that comes to mind at this time is an Euryops. This web site has a photo for you to consider:
Regarding the aster I can't know which one that might be as there are many and they all would be described in a similar way. A local botanical garden or your County Extension Office might be able to help. You can plant any of those plants with Angelonia but a 14 inch container is too small. The angelonia alone is enough to fill that container.
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