The concept of images per row is sort of nonsense especially if you have a responsive theme as it depends on the size of the thumbs and on the CSS of the theme used. So you will possibly have to modify the theme CSS of your theme. Best use the multiple_layouts plugin if you need a specific layout for certain albums.
The options for images per row/column are really dated legacy options that will be removed in the future anyway. Change the number per page instead.
Away to generate the Thumbnail from a frame in the movie? or,
Zenphoto cannot do this, it is not possible. You have to do that manually and upload the images as so called video thumbs (or sidecar images as the general term):
https://www.zenphoto.org/news/problems-with-albums-and-images/#------thumbnails-for-videos-or-other-non-standard-
You can display the title with the thumbs but none of the official themes does this. But certainly you can create your own layout doing that.
For videos you can also use for example jPlayer's specific function for a playlist (also requires theme modifications)