And if so, doesn't that trigger DOS?

Knowledge is power.Once you have purchased the community, you are going to need even more help and you are going to have a number of legal and compliance issues to deal with.

The seller disclosed the long term leases on two of the units, but only provided the expired, 2 year old lease and the rental increase notices for the other two  and did not produce the additional long term leases that tenants shared with me.I'm in a bind here, I can't break the leases and can't stay in compliance with the loan terms.I've already reached out to my agent, who is fortunately a commercial brokerage with an attorney on staff, but have not heard back.

Guidance on BIRT and NPT taxes is very limited and as the transactions get more complex compliance becomes challenging. 

Honestly if you still have these questions as your about to pull the trigger then you're not ready to pull the trigger.  

I waited until I knew enough about investing, to reduce my risk, before I pulled the trigger and made my first purchase.I'm taking massive action to acquire properties over the next 5-6 years and take advantage of the low interest rates.

I have been consuming knowledge for over a year, and it's time to finally pull the trigger!

Next, adding interest to an underlying loan, several issues, but your interest rate won't match the principal owing on the underlying mortgage this makes tax reporting and borrower disclosures difficult, beyond the financial scope of any small investor without a loan compliance department. 

If the law says it fine, your broker/agent agreement is in compliance and the customer is OK with it, your good to go.

So if the property has increased in value then you may be triggering capital gains.