Hi,
1. In the settings of the user points plugin, you can restrict it to categories. So create an unpublished category and add it as a second category to the products which should award points upon purchase and select it in your user points plugin.
That way, other products won't award points.
2. There is no such email for the user points payment plugin. Only the payment plugins receiving a payment notification from a payment gateway to confirm that the order has been paid receive such email. Since the user points payment plugin doesn't receive any notification and basically just allow the customer to purchase his products for free by reducing the amount of points in his account, when the order is created, you're already sure that it is a valid order that has been paid.
Actually, when the order is created, there is already an email sent to the admin called "order administrator notification" which even has more information in it about the order than the payment notification email.
So you could use that email. You could even modify it a bit to only send it based on the payment method used.
3. I would recommend turning off the "front end" display setting of the user points custom field because this allows the user to modify the value in the custom field (set it in the registration form, and modify it in his Joomla user profile). Instead, I would recommend to modify one of the view files of HikaShop to add some code to display the points of the user account:
www.hikashop.com/forum/discount-coupon/8...guration.html#199198
With the "Display view files" setting of the HikaShop configuration, you can easily see which view file to edit in order to add such code based on where you want it exactly:
www.hikashop.com/support/documentation/1...-display.html#layout