@Brett Michael
Ok, that is what I figured, but if you owned a college campus, your situation and my advice would be quite different!
Cannot answer all of your questions here, but will start.
First, I understand how frustrating it is, trying to learn all about RE investing. That was the point and premise of this discussion. I felt like that in law school, like drinking from a firehose. Just have to stay focused and be patient.
Regarding the duplex questions. First, it is important that you learn how and then always perform an analysis on any given deal. You take into consideration the rental income, purchase price, any repairs and fixup necessary, and the usual expenses associated with a rental property. These normally include an allowance for Vacancy, Maintenance/repairs, Cap Ex, Management, taxes, and insurance.
Depending on how you finance the property, you may also have a mortgage payment, which may include Principle and Interest.
Absent actual data and information, I usually use 10% for each of the 4 expenses (Vac, Maint, Capex, Mgmt) and often, the taxes and insurance are around 10% too.
So the typical Expenses assumptions I use, add up to 50% of the monthly rental income.
In your example, if the rents were $700, with tenants paying all utilities, then your 50% expenses would leave you $350 a month leftover to service your debt (Mortgage Payment) and anything leftover would be your net cash flow. If you paid all cash for the property, at $35K price, so have no debt service, then your cash flow would be about $350 per month. However, if you put 20% down and borrowed 80% at 5% rate for 30 years, your P&I mortgage payment would be $150 per month. That would still leave you $200 net cash flow. Everything being equal, this appears on paper to be an outstanding investment opportunity, based on what you shared. But that is just the beginning of the decision process for you. In other words, the pro-forma analysis did not rule OUT the deal.
You would then take a much closer look at it. We did not include any fixup or closing costs in the acquisition cost.
You would need to inspect the property and determine what work is needed and might be needed in the near future. And take that into consideration in your offer price.
Cannot say why the property may not have sold yet, you have to figure that out. It can be for many reasons, including the market, location, condition, and many other potential influences on the value, or a buyer's desire or interest in owning the property. Could even be incorrectly listed.
As for how can you pull money out of a property you own outright, to use for other investments, there are a number of ways. Obviously, selling it would be the typical method. Second, is placing a mortgage on it, and use the borrowed funds to purchase other properties. This loan could be a regular cash-out-refi or you could obtain a Home Equity Line of Credit (HELOC) on it.
Your low-ball offer question. Not sure how to answer that, even if I had more info. If that is a strategy you want to use, then you have to decide how many, and for how long, and how low, etc. People do it, BP just had a podcast with an attorney investor who bought hundreds of condos by making tons of offers each day. So it works.
Not sure how to answer your question about best financing option on a paid off rental. Need to clarify that.
If you purchase two separately platted houses, they will each have their own mortgage, but a bank might do a single note, cross-collateralizing both properties, but that would be odd and not serve any purpose I can see, absent more details. IF you meant the duplex and not two houses, and the duplex is actually a single parcel in the land records, then yes, it would be a single mortgage and note. Again, give more info on this one.
So always remember, answers can only be as good as the questions asked. The more detail and info in your questions, the more accurate and applicable the answers can be.
Hope that helps.