Hey Chris,
1. Yes, you need to modify the view (standard joomla template override). You need to modify the components\com_hotspots\views\hotspots\tmpl\default_hotspot.php file and move the {{date}} and {{created_by}}in the hs-hotspots-overview-short div.
2. It's possible, but what for? The browser has this awesome BACK button that is available on each page. There are mouses that have a dedicated back buttons, on tables you can scroll to the right to go back to the last page. So this is in my opinion not necessary. Also you have an issue when the user opens the hotspots in a new tab. Then the back button won't work.
3. You can achieve this with CSS. All kinds of the presentation can be modified with CSS
4. That's unfortunatly currently not possible
5. There is a userhotspots view in the PRO version. You need to create a link to it in the menu and when users click on it they will see their own hotspots.
Submission form:
1. you need again a template override for this.
2. You don't have to modify files. You can use the standard language override feature in Joomla:
docs.joomla.org/J3.x:Language_Overrides_in_Joomla
3. What do you mean with top of the page? The message is shown where your message container is. This message container is defined by your template and we can't influence it. It's the same place where all joomla messages appear.
4. Yes, you need to enable the hotspots - email plugin
Regards,
Daniel