Netlify CMS can edit JSON and markdown files, so you need to have somekind of SSG to output HTML/CSS/JS.
Netlify CMS can handle text, png, jpg, and audio and video is handled the same way as the images, meaning they will be uploaded to the same directory which you can reference later in you documents while editing.
There plenty of starter options you can use with, i would recomend using gohugo.io or eleventy SSG, they are easier to learn and very robust SSGs.
If you plan to stick with NetlifyCMS you can check https://templates.netlify.com/ and https://www.netlifycms.org/docs/examples/ for more option
If you plan to stick with Hugo check https://themes.gohugo.io/
If you plan to stick with https://www.11ty.io/docs/starter/
In any case i don’t you’ll find something which is completely satisfies all your requirements, so be prepared that you need to write some custom code, especially if you need animation. But in any case Netlify (and NetlifyCMS) should be able to handle all your requirements!