Yes, Leaf supports 8 post formats, aside, audio, gallery, image, link, quote, status, and video. When adding/editing a post select the post format you want to use from the "Formats" meta box.
Leaf has 3 page templates, blog, one column, and HTML sitemap
To use a page template add/edit a page and in the "Page Attributes" meta box, under "Template", select the template you want to use. The blog template will display your post, the one column template will be a wide page with no sidebar, and the HTML sitemap will make a HTML sitemap for your site.
Yes, you can download or fork a leaf child theme starter from GitHub Leaf child starter.
You can report bugs and feature requests on GitHub Report bugs and feature requests. Note: requires a "free" GitHub account.
You can ask general support questions on WordPress.org Report bugs and feature requests. Note: requires a "free" WordPress.org account.
No, but i am trying to figure out how to get it too. ;)