As I understand it, the "Status" field refers to the status of the development, not the program. The existing pages only have the statuses Finished, Active Development, Stale, and Abandoned. For example, Cave Editor is also stable, but its status is "Abandoned". Similarly, NX-Engine/Evo are stable, but development is no longer ongoing (until recently, the last commit was about two years ago), so they have the status "Stale".

I'm not sure what criteria the maintainers used to determine the status of the projects, but there is no "Stable" status, and I doubt it's necessary.

It's probably better to add the logo as a file in the img folder and embed it using a relative link (/wiki/img/{IMAGE}) rather than storing it as a GitHub attachment. This is the recommended way to add images (as shown on the example page) and is used on all other pages. Also, the width and height attributes are unnecessary, as their values are already contained in the image itself. And it is better to remove the alt attribute or set it to something like "Doukutsu Assembler Banner" (or logo), as this attribute is intended to describe images for humans.

Can't add it to the img folder, the project owners disallowed permission to add files.

You can upload files and push commits to the branch of your fork specified in the PR (in this case, patch-10), and then when the PR is merged, all these commits will be accepted too.