Does S3Media Stream support HLS adaptive streaming?

Yes, you can (with S3Media Stream Enterprise with a paid JW Player license).
Note: HLS adaptive streaming can only be embedded with a public web distribution because it makes use of various playlists to serve different bandwidth versions depending on the internet connection of the visitor. This makes the format prone to theft but you can set the bucket and the files themselves private to reduce the risk. There is a step-by-step tutorial in the support section that explains how to do this.
You can also use audio and 360 VR video with HLS.

Updated: December 18, 2017