we have tested it with HTML integration and it works.
Simply click on HTML button in a slide, then take a playlist from Youtube, eg: https://www.youtube.com/playlist?list=PLWPXhqX9nIxi_rV28PYmtRtsLodFVZ–k

Then click on the SHARE BUTTON on Youtube and copy the embed code. The code looks like this:

<iframe src="https://www.youtube.com/embed/SjOf3RJXG8E?list=PLWPXhqX9nIxi_rV28PYmtRtsLodFVZ--k" allowfullscreen="" height="315" frameborder="0" width="560"></iframe>

Just add these parameters:

<iframe src="https://www.youtube.com/embed/SjOf3RJXG8E?autoplay=1&listType=playlist&list=PLWPXhqX9nIxi_rV28PYmtRtsLodFVZ--k" allowfullscreen="" height="315" frameborder="0" width="560"></iframe>

Also this behind the Video ID: autoplay=1&listType=playlist&

Now the Autoplay will work and all videos from a Playlist will be displayed!

Other Youtube parameters you can use can be found here: