If you're already in negotiations with the 1st, ask them how much they will allocate to the 2nd mortgage then adjust your HUD accordingly and get everything submitted to the 2nd for review.

A lot cheaper, quicker, and easier than trying to get it re-zoned.

I work at a large national bank here in Minnesota and have been working with my regular mortgage guy there. 

I have six mortgages on other investment properties and no private residence.

These things are everywhere and the prices thrown around are scary for people who own expensive real estate and charge people rent to live but if options come up that are that much cheaper that's not good news for us. 

Even so, the mortgage lender informed me that due to federal laws, the way student loans are reported has a significant impact on the amount I can be provided. 

I bought a 4 plex with 25% down and a conventional mortgage.

.$500 mortgage payment - how much are you planning to put down?

I want to do a conventional mortgage.

Consider using mortgage broker to help you find the right lender.