Option pricing is not arbitrary, you don't just pull a number as to what you think you can get out of someone as your deal could become predatory dealing, that's an issue when the deal blows up and most options blow up.Credit of an option price to the sale price is customary, but not required.

I purchased a home for $42,000.00 and it currently is rented out for $800/mo by the same tenant for the past 6 years. I want to put a mortgage on the property for $65,000.00 to do some other business. The home current...

I've been to the county sure to pull up the tax records but the homeowner address is the same as the vacant home.

Rate will be higher though and you could pull some cash out if you like.  

If you can afford a higher mortgage payment on your live in property, you can also pull equity out of that, but I would leave it alone. 

you will do great as long as you take the first step, and pull the pin, the biggest mistake most wana be's make is never taking action. dont fear it, take action. be sure of your numbers, fall in love with the DEAL, and NEVER fall in love with the Property. you have plenty of potential in that area, find your farming area, and cultivate!!!

The bank won't let me pull out all of the equity because it will push me over the 40% for debt to income ratio.  

I'm looking to pull money out of a mortgage-less property and use the money for other real estate investments.

I am quite sure now that I am a little older and wiser I could pull it off.

Sounds like you are well on your way and will be pulling the trigger soon, I think at this point you should have been able to conduct enough studies to determine the major challenges that exist as you define multi and single family.