Hi Paul,
Asking too many questions on the same topic should be hard to search for another customer. So I want you to create a new topic for your each question next time.

1-2 ) You should go to appearance > customizer > featured area and play value for the widgets. So can also watch the video on the theme page. We just showed how to customize the featured area. You can do many customizations on font, size, spacing, color and etc. Play with the “SLIDER TITLE TEXT RATIO” value to adjust the font size for slider and related post titles.

3) When you go to customizer > blog > you can control the excerpt length and width as well. Currently excerpt length only works for blog regular layout, we plan to add a new option for blog grid/list excerpt length with a future update as well.

4) We dived the footer area to 4 column. You can just use three of them and use this custom css code;

@media (min-width: 768px) {
  .footer-widgets .col-sm-6.col-lg-3 { width: 33.33%; }
}

5) You can try to use this custom CSS code;

.post-thumbnail .entry-header.ready { opacity: 0; }

.post-thumbnail .entry-header.ready:hover { opacity: 1; }

6) http://themes.pixelwars.org/theblogger/default/home-alternate/
You should add the intro widget to page featured area.
Then create a page for the homepage and choose latest post template on the right-hand side.

7) https://wordpress.org/plugins/mailchimp-for-wp/
You can use this plugin or use pop up convertplug plugin which is embeded to our theme.

8) You don’t need to update the premium plugins. We will add the latest version if the plugin author release an update.
Thanks