Can you benefit from it when you are actively doing business, absolutely yes. 

I don't think applying for a loan right now is of any benefit to you, as your husband isn't going to be on it so you can't use his income toward it.

The benefit would be you would know how much each unit would use, the inconvenience would be that you would have to monitor the flows and modify the S/W/T bills for your tenants accordingly.  

The side benefit is that you may come across other deals that, if you dont want them, you can wholesale to other friends who are investors.Do some research on marketing for properties or read some books.

The advantage of having an up-to-date RE accountant, is that they can help you strategize utilizing tax benefits, that a non-specialist may not even be aware of.

I have $50,000.00 to invest and I found $70000.00 patio home. so I decided to buy with 20%down and get the traditional mortgage but quickly realized that I have to pay roughly $3500.00 load processing fee to get the either 15yr or 30yr loan. question #1 should I use HELOC(which processing fee is in 7 to 800ish) from my home to pay the rest 80% and try to pay off as fast as I can or just get the traditional loan and utilize the tax benefits?

The main highlight or benefit of Fannie mae's 1 year tax finding is that you dont need to prove 5 years in the same line of work which is a harder burden of proof for most realtors or business people. 

Some benefits I have noticed while househacking in my triplex:- I am at the property daily and can stay up on any maintenance and issues without having to remember to drive by or check in with a property manager- Rent collection is as simple as a door knock.- Tenants generally will be less inclined to try any funny business because they know you are right next door (or above/below them)- It's more conducive for learning as you go.- More favorable loan and insurance terms for an owner occupied property.There are also downsides such as:- Less privacy- Blurring of the landlord vs neighbor relationship- Can be harder to be the "bad guy" on things because you see your tenants often.

The only benefit is no down payment, which to most doesn't end up being a benefit at all.The thing I did was save before I bought. 

Shawn, as a "disqualified person" to your IRA you are not allowed to receive any personal benefits (using investment as a residence) from your IRA.