After reading this article, I feel that the author could also mention that the concept of serverless could be taken one step further by using S3 static web hosting. After all if you’re using api gateway and lambda already, then another option would be to call your API directly from the client. This would eliminate the need for EC2 container services and the infrastructure to host server rendered web applications, along with auto scaling and elastic load balancer. Remember simplicity is a good thing. I would recommend not using Cloud Search, as Amazon has stated they will soon be discontinuing this service in favor of Hosted Elastic Search. I would also use Elastic Transcoder cautiously, if these videos will be internally provided and not uploaded by the users of the application than this service may be over kill.
Obviously there is no one size fits all solution, and I am always appreciative when folks take the time to write about these topics, so these are just some opinionated comments I wanted to put out there.