The contract language will be key as it may release the tenant from all responsibilities or only from penalties/fees.

I'm currently seeking a owner finance deal.

End the accounting with the admonition of where they need to send the money they owe you.This will keep them from seeking out an attorney to litigate the matter. 

If audited, the repayment penalties and interest are serious. 

It's a bad idea to lease option to seek out lease options from preforeclosure sellers. 

If you built the garages, installed the pool, etc without permits and inspections, you'll have many more problems with getting those passed by your township than you may think.The solution I would recommend is to have your parents refi, put the property into a trust, you can be a co-beneficiary, and when you can afford, give them whatever money you have agreed to and have them quit claim their beneficial interest in the trust to you.I am a realtor, not an attorney, so please seek out a qualified attorney to get you set up. 

Section 1031 in the U.S.A. is considerably different and allows you to exchange (upgrade) assets.I would also disagree that having four residential mortgages in your own name precludes you from seeking additional ones from conventional lenders.  

Engage the local municipal and state governments who are seeking and redistributing these grants.

Tenants should be allowed to cancel their lease without penalty if they claim they "can't pay rent".   

I know it's a bad time to take it out due to the stock market dive, but with the 10% penalty removed I'm tempted.