Your IVA should have no adverse affect on her application -- but you should check this specifically with the government department concerned. You are correct in that you would not get a mortgage. Renting is not impossible, but not made easy. You will fail credit checks, but some agencies / landlords will accept higher deposits, advance rent and / or a guarantor to overcome this. The other alternative is to rent privately, direct from the landlord (i.e not through an agency) where a credit check might not be made.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk