GIFs are not supported for the time being but you can add a YouTube video instead.
The issue with paid extensions being listed as free if they aren’t sold on EW is our list, but sadly we have a staffing shortage on the Extension Warehouse team and not a lot is happening. We all just need to be patient for now (it’s frustrating for us too).
Regarding the presentation text of this extension, I would personally use a more precise/descriptive name. “Simple Architecture Tools” for instance gives a better idea of what the extension does. Remember that not every SketchUp user nor every extension is in the architectural field.
For the copywriting I would personally try summarizing on a higher level what the extension is for instead of listing the tools by name. For instance you can say it’s an architectural toolset that allows you to draw walls and openings very quickly, and allows you to easily edit these objects. I would also focus on what sets the extension apart from other house-drawing extensions. This extension seems very well integrated to the SketchUp user experience, with e.g. support for the native Move tool, axis locking, the same appearance of the protractor etc. While it’s probably not relevant to list all these design aspects, there could be a sentence stating the objective of consistency to SketchUp.
Hope this helps!