Does the IRS issue a levy after IRS Letter 4223 is mailed?

You need to consult with a tax lawyer, ASAP, regarding your IRS liabilities. There are "collection alternatives" to levies.

You need to pursue with IRS a "collection alternative." And, then, you would not have to worry about enforced collection, including wage garnishments.

Should a spouse request a non attachment certificate if there is a lien on the primary residence placed by IRS for unpaid taxes

More facts are needed. In this regard, you should consult with a tax attorney to review your facts and advise you accordingly.

I owe back taxes, the IRS has a lien on my home. Can they take inheritance money I receive ?

Yes. You need to pursue with IRS, ASAP, a "collection alternative."

Can I file single if I am married?

You cannot file single, if you are married. However, you can file married filing separately.

Pending audit 2015 with amount owed $30k. Should I agree on amount and file OIC later on with the collection dept?

If there is serious doubt as to your liability, you should challenge the proposed audit adjustment. And, if successful, there would be no need to...

Change in Terms To Offer in Compromise

The best approach would be to make an "offer on an offer." The new offer would take into account your changed circumstances.

Could I still file my taxes from 2 years ago if I have lost my w-2's?

Yes. And, indeed, you are required to file. In this regard, IRS has records of the W-2's.

Can the IRS garnish my VA disability and if so how much can they garnish? and can they "take money out" of my bank account?

IRS has enormous collection powers and they use them. The good news, however, is that IRS has "collection alternatives" to enforced collection. You...

You need to pursue, ASAP, a "collection alternative." Once your case is thus under control, you will not have to worry about IRS levies.