PSW Dependant visa while main applicant is in home country.

Hi,
I am doing my Masters and currently in tier 4 visa. I have done my undergrad from UK as well. I will get married next month. My fiancée hold a PSW visa which will expire on September'2014 but she is living in Bangladesh since January'2013 and working as a teacher there. After getting married, we are planning to switch my visa from tier 4 to PSW dependant as my visa expires on January'2014. And she wants to come to UK for searching better opportunity. I know tenancy agreement is not mandatory but if my cousin who is a landlord gives us a tenancy agreement in her name while she is not in UK, would it be acceptable? or it's better not to attach it with visa application? and second thing is, can she use my address for her bank statement? would it be questionable, as she doesn't have present establishment in UK but she will be using a bank statement with UK address? what about using a Bangladeshi address as bank said they can do it by making this account an offshore account? finally, does tenancy agreement's address and bank statement's address need to be same?

I am very sorry for long text and but I had no other choice. I couldn't book my air ticket just because of this confusion. Your advice and time will be highly appreciated.