my wife got a form g-56 request for bring all the docs for interview on i-485 on 11th.

1. Is it usual to get g-56 instead of i-797? My wife had overstay on her H-1 before my filing i-130 but she got her i-131 and i-765 approved.

We just filed 2009 tax by CPA firm. We can't get official tax doc.

2. Do I need ask CPA firm to issue a letter certifying that they helped us file the joint tax return? other option?

Background, we don't have joint lease, or joint-ownership of house, car etc. only have joint auto insurance, bank account, credit card but not very active, but we did travel together a lot.

3.Our evidence may be weak?

4. Will an affidavit of neighbor who can testify us married,living together be helpful at this stage? the more,the better?

Appreciate answer asap.