Redirect page after purchase

You could try to editing the after_end view file via the menu Display->Views. There, you will have access to the $this->order which contains all the order information and you will be able to do your redirect.

Alternatively, you could just create custom fields of the table "order" (Business edition only) and they would be displayed on the checkout and the values entered by the user would be attached automatically to the order (and the emails). It's way easier to do.

Redirecting can be done like that:

$app=& JFactory::getApplication();
$app->redirect(' myurl.com/index.php?option=com_breezingf...&view=form&Itemid=84 ');

Redirecting to the page where you have the form with the code posted before sounds to be the best solution to what you're asking.

Please make sure that you're editing the correct view file of your front end template and that your payment plugin doesn't have a return URL configured. Otherwise, you wouldn't get that page displayed.

Emails can be edited via the menu System>Emails in the Business edition.

The modification is correct. But make sure that you're doing it for the correct template. You should have once instance of that view file for each template on your website. If you have several templates, you might not be editing the view file for the template you're actually using.

Also, for some payment plugins, it's the file "end" of the view "checkout" which should be edited instead of the "after_end" file (when the payment happens on your website or when you're using offline payment plugins like the bank transfer).