Ideally a scalable solution that supports queues and uses a relational DB for easy migration to AWS in the future should the product scale. Ideally trying to avoid getting locked into a limited platform and needing to kludge around it
The use-case you're describing could be a great fit for the tool we're building: stacktape.com.
It offer the simplicity a productivity of a PaaS platform directly in your own AWS account. It supports all of the infrastructure components you've mentioned.
It's a tool made for developers that want to deploy their apps to AWS without having to learn all of the DevOps/Cloud/AWS knowledge.
Unlike other PaaS platforms, Stacktape deploys your apps to your own AWS account and allows you to extend/override anything, giving your the full control and minimum amount of vendor lock-in.