Better to spend a couple hundred bucks than to lose thousands because of a quirk in the law you didn't understand.. 

@Roger Evans a 12 % return on your money is a reasonable amount if you understand the risk.

I'm sure there are a lot of things I don't understand about this so any light shed on this would be very helpful.

But understanding why it has been vacant for 12 years is the key here.

I realized that getting sellers means nothing if you don't understand what your potential buyers are looking for.

It's been my understanding from the research/coursework I've done that this is almost certainly against their primary mortgage's terms.How common is it for banks to call loans in these situations & how safe is it for people to offer seller-financing in these situations?

But they have all standard reports that are easy to understand and interface is user friendly.Hope this helps. 

As I understand your objectives, you want a commercial real estate asset that will produce income for you.

From my understanding this is the rate when considering all associated costs correct?

If you read both, you will understand that I need some serious help.