2.) The plugin already uses the most preceding style that matches with assigned to the tag you use for its entry title (header).
For example: If you use <h2> for the title tag, it uses whatever H2 tag styles the theme has. (title tag is set within WPSP “Content” tab)
3.) Unfortunately, we can’t give a set date yet as Tom has his hands full with GenerateBlocks Pro and fixing bugs caused by WordPress 5.6 release.
Again, we’re very sorry for the delay in response.