Excellent write-up. I think when dealing with messaging systems it's important to know the difference between Pub/Sub vs Point to Point models or Topics vs Queues.
Can you technically use a Queue as a topic for pub/sub? Yes. But should you? Probably not. You're much better off not using SQS for that and instead using SNS.
I wish SNS had a way to have a process receive a message, or have a Watcher for it in an AWS SDK like Boto. Feels like a big hole in actually using SNS as a pub/sub mechanism. Much simpler than having to setup and maintain an HTTP endpoint.
Can you technically use a Queue as a topic for pub/sub? Yes. But should you? Probably not. You're much better off not using SQS for that and instead using SNS.