1. Presumably you have been doing your research and checking out the features list for the themes, and if you haven't already done so, you can find the Clipper features on the main theme page
here. We also have an AppThemes marketplace where you can purchase add-ons for our themes
here.
2. Yes Clipper is W3C valid and
SEO optimized.
3. The promotions we have available at this time are related to
WordPress Hosting or
AppThemes translations so you are welcome to check if either of these may apply.
4. You can find theme release status information
here. Upgrades are relatively straightforward if you haven't customized the theme, but if you are planning to, we would recommend you create a child theme to avoid losing all of your modifications during an update.
5. The ones in the
AppThemes customer showcase are submitted by customers, otherwise you're welcome to sift through the
showcase thread and see if any are mentioned there. Thanks.