vankaa

By default downloadable/virtual products will not be shipped, so shipping will not be calculated.

There is no “options amount” and “final total” in WooCommerce, so please be a bit more specific

You can try using the 'woocommerce_order_number' filter and instead of changing the order ID, change the visual order number.

You want a space between the name and the category add a space before the label

$name .= ' <label>' . $taxonomy->label . ': </label>' . implode( ', ', $terms );

You want to show it under the title, you can either add <br/> break before the label or add a class to the label and style it as a block element.

On Add to cart you add your category group to the item data:

// On Add to cart add the item custom data
add_filter( 'woocommerce_add_cart_item_data', 'prefix_add_cart_item_data' );
function prefix_add_cart_item_data( $cart_item_data, $product_id, $variation_id ) {
	// Add your logic to find the item category group.
	$category_group = "RAZ CHRISTMAS";

	$cart_item_data['item_category_group'] = $category_group;

	return $cart_item_data;
}

Than in cart you have to split your items into their respective groups. For each cart you will replace the global totals with the totals of the respective group.

For checkout you can either remove the other groups from the cart and just checkout the one that was chosen or filter the order total and the items displayed on the checkout page.

As I said before, this is not something that you do in couple of hours. There are quite a few changes you will need to do.

Firebug was replaced by the FF developer tools, just press F12 and you have it. The same thing you can use in Chrome.

.woocommerce-mini-cart__buttons a.button.wc-forward:hover {
    color: #fff;
    background: #DC0E0E;
}

#ttr_content_margin .woocommerce-message a.button.wc-forward {
    color: #fff;
    padding: 6px 12px;
    font-size: 16px;
    font-family: Arial;
}

You did define an attribute, but not its options. It is like telling WC, “I have t-shirts in attribute “color”, please create my variations”. The logical question is, what color? Even if you go to the admin, create a variable product then add attribute “color” without options, this attribute will not be saved.