What name fields do I need for an informal registration form in Arabic?

I want a friendly, informal registration form for users who speak either Arabic or English.
Since we use an informal tone, we want to be able to send emails using only the first name, not the full name.

So, what fields do I need and what should I call them? Are there any recommendations/best practices?

Currently, I'm leaning towards "First name" and "Last name" because

• It's simple.
• It's well-known.
• Facebook is using that format, 1B people managed to sign up..