WordPRess payment VAT customisation

The Website is built on WordPress and the memberships module is built with Paid Memberships Pro. We have a plugin that manages the amount of VAT applied by EU region and applies that amount at checkout. We provide 6 subscription levels but not all of the 6 packages we offer are subject to VAT. Also we require the total to be inclusive of VAT and not +VAT as it is currently. So we require: - A way to make certain subscription packages exempt from VAT - Make total inclusive of VAT where applicable - For those packages subject to tax, when the member's state is selected from the dropdown menu the order total is updated to include the tax before proceeding to checkout - In support of the above we may need the total to be moved on the page. - The correct value is reflected in the generated invoices - No hacking of any of the website's core, themes or plugins. The plugin code must sit independently, as a stand alone plugin We also require some invoice template to match a invoices we have previously used i.e. add address details et