2nd mortgage vs. rent to own

[Brad Klock]

Ok so this is somewhat complicated but I'll try to be as descriptive as possible. I bought a SFH and remodeled it. All in I am sitting at 27K (4 bedroom 1.5 bath) turned out beautiful! So I started a cash out refinance and was going to rent it out. The plan was to take 28K out and get a LOC for 30-40K to purchase the next place. The rent was going to be $600 + utilities. Now is where the curveball comes into play. My cousin (who is like my brother and very reliable and pays all his bills on time) wants to purchase it. I set the selling price at 68K, however since he is not divorced from his wife (they have been separated for around 4 years) the bank could not take his income into play because he is still technically on his first house mortgage. His girlfriend has never purchased a home and only qualified for around 50K. I am considering letting them get a mortgage from the bank on 50K and having a second mortgage for 20K that would be paid to me. Or possibly a RTO situation, however I am not sure what would be best at this point and exactly how to go about it. If I hold a 2nd mortgage I would get 50K at closing which is only 8-10 less than what my LOC would be for and then I would finance the 20K as a 2nd mortgage over the next 10 years. Which sounds nice because I have all my money back plus more to go buy more properties and still have the income of the loan payback each month. Someone please point me in the right direction here because my brain is cooked. I have never done this before or a RTO for that matter so I am in desperate need of advice. Thank everyone in advance!