for the delivery charge, if you recall, we had added a Set Session value behavior of the confirm page, since the paypal standard form posted to the confirm page, with express checkout, the checkout page posts to itself now, so the set session value behavior for the delivery charge needs to be on the checkout page.
i cant see why product options should cause the page to go to the failure. Go to the bindings panel, click the plus button and select eCart -> Checkout -> Local Checkout response.
from the gateway select list, select Authorize Express Checkout, repeat this and select Process Express checkout.
expand each of these binding groups and add the full response and full request bindings, this will help troubleshoot the problem.
where you say this is time sensitive and need to go live soon, i would suggest the premier appointment as the quickest way for us to resolve these issue with you.