there is no bank, no mortgage, and therefore no due on sale clause.if there is a mortgage in place, and you take the payments over, this is typically referred to as subject-to or sub2 and is much higher risk for everyone involved.

If you're lucky enough to get a free and clear property where the seller is willing to finance, this reduces much of the risk associated with seller-finance.I would make sure the title is then moved over to your name, especially since there is not a risk of a due-on-sale clause being triggered.

Don't start throwing ideas at them like seller financing or numbers etc until you have an idea of if they actually intend to sell and what their needs are around the sale.

Defending, These fall into a couple of groups, both nasty Eventually you will either face a Due on Sale clause, a seller bankruptcy, a court order in a divorce that affects the property or a fire insurance claim, a slip & fall, very bad tenant, storm damage, and the list goes on.

My property is in 5th ward but in a more gentrified area with several new builds on the street that are occupied and 4 more being built on the street that are all for sale.

Real estate agents tend to want to make a sale and they are not as experienced with the rental market as they are the sales market.

(We had already given them a reduction on the sale price under market.) 

Interest rates doubled within a six month period of time and property sales almost completely stopped. 

Raising money is all about marketing and sales (not real estate specific) so either hire marketing agency and read sales books, or hop on some LinkedIn courses on marketing and sales.Not sure the legal structure to use: talk to accountants and attorneys.Need deal flow: talk to brokers and go to a lot of networking events.Lending terms: start calling banks and loan brokers.From there, it is all risk mitigation. 

Also, I'm not sure how you're paying attention to it on the tax side, but the unit that you are living in's profit at sale is calculated differently than the other unit that you're renting out.Once you move out, that unit is officially available for rent so from that point forward, any profit gained at future sale will be calculated starting from that point and will be taxable.