Dear,
1) Do you mean this documentation https://www.8theme.com/demo/docs/woopress/ ?
All available settings for WC pages you can find in Theme Options > Shop, Products Page Layout and Single Product. Default settings for such pages are in Appearance > Customize > Woocommerce. Because WC pages are default pages of the plugin, you need to use custom css code to change styling.
2) Because of the current content structure, the single product page can’t have full-width background color as you described. Additional customization in files is outside the scope of basic theme support, sorry.
3) This code:
.single-product .meta-title span {
background-color: transparent;
}
.single-product .product-navigation h4.meta-title:after {
left: 53% !important;
width: 47%;
}
will give you such result – http://prntscr.com/pu9rn1
4) Provide screenshots of mentioned borders. You can use Lightshot Screenshot tool https://app.prntscr.com/en/index.html and provide the link to screenshot here.
5) Google plus was removed from 8theme – Social links widget in the latest version of the theme – https://themeforest.net/item/royal-multipurpose-wordpress-theme/8611976
Instagram API doesn’t have share function and can’t be included in share icons.
Regards