>The restaurant wishes to enable guest checkouts to increase conversion rates whilst maintaining the ability to Remarket email and SMS promotions in the future.

and this would be completely illegal. never mind GDPR (which may or may not apply to that restaurant)
it’s simply called SPAM

I am sure there are plenty of wordpress plugins out there that let you export registered users with whatever data they chose to register

and there’s also the “WordPress -> tools -> export personal data” option (WP 4.9.6+)

really depends how it’s setup in the first place
if you have something (in this case Onions) preselected, the customer can just de-select it
if it is only in your description that an item has onions, then of course th eplugin will not know anything about it
however, you could simply add a “No Onion” topping so to speak a customer can then select (you could also set negative prices
there if you wanted!)

Naturally, the customer can of course also write “no onions” into a textbox

> but now I have just activated.
and i dont see any popup anymore….

…you must define a homepage of some sort in wordpress

i cannot comment without a link to the site in question

have you checked the wppizza/logs directory for any error logs in there (or indeed your debug.log provided you enabled debug)

in fact, it might even work by simply dequeueing the jquery-ui-[selected_style]-css and rerequeing it with a lower priority so it gets loaded before any of your other stylesheets so those (i.e your datepicker) simply overwrite the set styles
without having to check for post_id’s and whatnot

mileage will vary. really depends on what the other styles do

>On the settings page
I assume you are referring to the *order* settings page

>Can each menu item specify whether a delivery charge will be applied or not?
not natively in the plugin, however, there is the following filter you could use to substract the delivery charge if a particular item (let’s say with id 5) is in the cart
I also assume you are using “Delivery Charges per item” in the settings here

So, something like this (not tested, mileage will vary, but should give you an idea):

add_filter('wppizza_fltr_delivery_charges', 'my_prefix_delivery_charges_filter', 10, 3);
function my_prefix_delivery_charges_filter($delivery_charges, $cart_items, $general_parameters){
	global $wppizza_options;
	/* current set delivery charges per item */
	$dcpi = $wppizza_options['order_settings']['delivery_charge_per_item'];
	
	$reduce_delivery_charges = 0;
	foreach($cart_items as $items){
		foreach($items as $item){
			if($item['post_id'] == 5 ){
				$reduce_delivery_charges += $dcpi;	
			}
		}
	}

	/* substract */
	$delivery_charges = $delivery_charges-$reduce_delivery_charges;

return $delivery_charges;	
}

of course dequeueing things (or similar) on pages that – one day perhaps – have datepickers and spinners on them will break things

sure, if you want to style ui-elements with your own css instead of taking advantage of the themeroller css options, you’ll spend a lot of time doing this and – in my book – is a complete waste of time as not only are you trying to re-invent the wheel but also have to know each and every class etc etc that ui-elements use whereas if you use what exists you can sinply forget about all of that

you dont even have to know what the classes are and don’t have to ever worry about updating anything when versions or whatnot change.
For example, currently wordpress uses 1.11. One day wordpress will probably be using 1.12 or higher. If you use your own css, you’ll have to maintain it.
Do you really want to waste your time checking for this every time there might be an update to something ?