How to translate the title "spgateway payment notification : payment confirmed"

Hello,

First of all, you can custom your email, for this click on the email name to edit it, and you can use the Help button in order to see documentation about email customization.

Now in details, for your first point, if only your email title is in English that means maybe that your language file have been edited but not this specific point, you have to edit your language file for this go in YourWebSite/language/YourLanguage :

Around line 644, you will find all email translation, and then you will be able to edit it, don't touch the translation key by example "ORDER_STATUS_NOTIFICATION_SUBJECT", see this documentation to learn more about this

for add the customer name where you need, you can use this tag {VAR:user.name} anywhere you want in HTML VERSION part.
You will see details about this, in the help button.

Hope you will achieved what you need.
Regards