Resolved, I was not in a site with the blog_id equal to 1.
It was not the version that was suppressing the “sync” and “copy” check boxes; it was the blog_id. You can only “copy” or “sync” when you are in a site with a blog_id equal to 1.
The “include in future new sites” and “sync role to all site now” check boxes are missing in version 1.5.1.
