APPLICATION AS A DEPENDENT CHILDREN OF A SETTLE PERSON

[malser]

Hello,
I am a British citizen, i am married outside United Kingdom. In 2016, i brought my wife to United Kingdom as my depend. However, We have 3 daughter 12, 8 and 6 who are currently not in UK. I want to apply for their visa. I need some advice and i will appreciate if anyone here can be kind to me with some answers to the following questions:
1. Do i have to make separate application for them?.
2. If i make separate application, do i have to provide 3 separate original supporting documents or i can use only one original and photocopy supporting documents?.
3. I want to submit the supporting document oversea but i will not be present in submitting the documents instead a relative will submit them for me, so who will sign the application VAF4A?.
4. I have signed a tenancy agreement with an estate agent but i will not be moving into the new house at the time of my application, so which address should i put on my application, i.e my current address or the new house where the tenancy will not start at the date of my application.
Please i will grateful to anyone who can help me with some answers and advice