Hi,
I have several question regarding your requirement:
1. About the email notification, you only want to fix it for Paypal IPN or for all other payment gateways? If for other, could you list them?
2. About the private discount, do you have only one code that can apply to all customer or each customer given their own code? And discount is for all product or each product have different discount, or discount based on amount purchase?
3. About the Google Webmaster, I am not so 100% sure that I can fix it until I have the access to Google Webmaster and your site.
Regards,