I didn't take any relationship statement, So i dont' think you need any relationship statement. However i took LALPURJA of the lands we own.
You don't need any translated or any property statement. Just take the Lalpurja....
The lady consular didn't even open my File. All she looked was my I-20 and she asked few questions like:
(1) Why did you come to Nepal ?
(2) What are you studying ? Are you doing any research ? What's the Topic of your Research ? Who's your advisor ?
(3) When are you getting married ?

Thats all. Be prepared to answer above questions.

Let me know if you have any other questions..