Not to mention that he might not stick with AWS if he runs the numbers- he might hop ship to a different cloud provider if he gets a better deal. I don't think it's appropriate for such a fledgling enterprise to lock in to AWS-isms so they can keep the change provider cost as low as possible.

Also, people seem to be dismissing the value of a rock-solid local end-to-end dev stack which with the latest iteration of technology I feel has become very complicated and expensive. The OP can run the same Ansible for his dev stack as well as his prod and his dev stack doesn't turn into an AWS bill. Most of the AWS managed tech & services is only reliably testable on AWS at a functional/integration level, which is a cost that a company this small shouldn't have to absorb.

Not sure I agree with the anti-lock in sentiment. It's a nice to have, but if what you know well is AWS or GCP or whatever, definitely lock yourself in.