1. I have commented following code in wp-content/themes/royal/woocommerce/sigle-product/cart/cart.php:
<?php// do_action( 'woocommerce_cart_collaterals' ); ?>
2. You should not be worry about this messsages it won’t affect frontend anymore. We update our theme from time to time and current theme version is fully compatable with woocommerce 2.3.8.
3. i have enabled cart widget in theme options->header->cart widget
4. You should have regisration page created to enable this option. Please read here about how to create registartion page: https://www.8theme.com/demo/docs/royal/index.html#!/4_registration_page.
5. Sorry for inconvinience. Sidebar cannot be removed from backend admin panel completely. Please navigate to the appearance->widgets to and add empty text widget in to the shop widget area . You may also select right sidebar position to move empty space to the right or customize wp-content/themes/royal/woocommerce/archive-product.php with text editor.
6. Please add following code into the custom.css to hide sorting options.:
.woocommerce-ordering{display:none;}
7. I was able to add short desription from product page as on the screeshot; http://prntscr.com/72h5cq;

With best regards
Brian Johnson

Sorry for misunderstanding. You may change it to black or any other colour. Please also add border:none!important; for both parts of previos code with :hover and without it.

With best regards
Brian Johnson

Hello

We have just added that code. You may use this 2 lines to restore alignment:

.fixed-header .navbar-collapse.collapse{display:table-cell!important;}
.fixed-header .navbar-header{padding-top:20px}

Please describe or provide us with picture of how it should look.

With best regards
Brian Johnson

Please this line before }:
color:white!important;
to this code:

.tp-caption .btn .medium .btn-white{
border-color: #fff !important;
background: #fff !important;
}

With best regards
Brian Johnson

Hello

I have edited a bit previously added code. please check your site now.

With best regards
Brian Johnson

Please provide us with screenshot or describe widely what you would like to achieve. You may use this or similar service: http://prntscr.com/.

With best regards
Brian Johnson

Hello

Please check your site again. We can see that it works fine.

With best regards
Brian Johnson

Hello

Thank you for this clean test procedures you are going to perform.
We are looking forward to hearing from you.

With best regards
Brian Johnson

Please clear your browser cache or change browser and check again. This is screenshot from Opera browser: http://prntscr.com/725hsd .

With best regards
Brian Johnson

Hello

Please provide us with screenshots where we can see the issue. You may use this service: http://prntscr.com.

With best regards
Brian Johnson

Hello

Please add following code into the custom.css:
.woocommerce-checkout-payment{display:none}

With best regards
Brian Johnson

Hello

Please provide us with wp-admin and ftp credentials to your site.

With best regards
Brian Johnson

Hello

You are welcome!

With best regards
Brian Johnson

You are alway welcome!

With best regards
Brian Johnson

Hello

You may add following code into the custom.css:

 .navbar{ padding: 10px 0;}
.page-heading{margin-bottom:0px}
.product-images, .product-information{margin-bottom:0px!important}
.tabs.accordion .tab-title:first-child{margin-top:0}
.page-content .product{margin-bottom:0px!important;}

Here is a video tutorial how to create custom.css: https://www.youtube.com/watch?v=Qok2zRedRMY&feature=youtu.be.

With best regards
Brian Johnson