unless this property is unsalable on the open market or your selling it for far more than its worth this is a Pass full stop.. 4% is not even close to market rate for seller financing it should be 8 to 10%and if you need cash then you have factor that into their down payment.

They are offering a 12-15 month 0% APR Credit Business lines, isn’t hard money usually a higher interest rate?

Their interest rates will be higher and they collect origination fees so the purchase price of the property is key and determining your ARV. 

$75k is best used for another house hack that way get a better rate and lower down payment meaning can put some of the money in rehab.

Currently, I'm only offered 27 hours of work per week at an average/below-average pay rate, which isn't nearly enough to save for a down payment or qualify for a loan.I've tried selling belongings to generate extra income, but it's not sustainable in the long run.

.- Only allows Rate/Term but we could add a HELOC on top of it to access cash in this instance up to 95% CLTV.Long story short, there are ways but you'd have to get creative and be over 62. 

Let us discuss how to finance properties if you don't have a W-2 job, what are you all doing in this high-interest rate environment, what are the benefits of single family housing verses multi-family, vs self-storage. 

You can also get a lower rate on a 30 year fixed and even though its a 30 year loan there is No prepayment penalty so you can pay as much as you want but not obligated to pay more.A Heloc is a credit risk and can "never" be used as an asset or PITI reserve which is required when buying additional properties.

I'm a little concerned with the current high interest rates and property taxes (Texas).  

However we would be "getting more house" ( access to a second back yard, tool shed, driveway, second storage unit, etc)When I look at other houses in the area, with the intrest rates as they are, I don't understand why anyone would buy multifamily and rent it out when all of these calculations would be negative cash flow.