Wow, you are really getting a runaround! It sounds like your Loan Officer suffers from the age old "LOD" or "Loan Officer Disease." I've been a Mortgage Loan Officer for 22 years and I've seen way too many LO's suffering from severe LOD.
Symptoms of LOD are exactly as you describe: poor communication, zero follow-through, flimsy prequalification, an inability to provide an honest answer as to whether or not you're qualified, and clear unfamiliarity (based on your post) of basic Underwriting guidelines.
Here's a link to local Mortgage Bankers in your area, Saginaw MI. http://business.intuit.com/directory/g10963-saginaw-mi/c1741-mortgage-bankers
I strongly recommend you work the phone this morning and find an experienced, LICENSED Mortgage Banker and schedule a face to face meeting with all your documentation. You'll get an accurate and prompt answer as to whether or not you are qualified for mortgage financing at this time.
You can verify the License and EXPERIENCE of any Mortgage Loan Originator on http://www.nmlsconsumeraccess.org/
If you want to get a straight answer and close by December 20th, you'll need to work pretty hard today and the next couple of days to make it happen. I'm sorry that a knucklehead in our industry has given you the runaround.