Discuss with your lender your financing options, particularly low downpayment options.

If I use my HELOC fund to buy a property, which of the following two options should I go with from tax or business accounting perspective?

If it is really low, like 3-5 percent, then at least as far as that point goes it would be worth doing it myself.

We have priced in the low 7’s for well qualified situations to much higher.

The bar is pretty low for most real estate agents. 

I think 150k is going to be too low like most folks here have said. 250k is a doable number. 

Essentially your net return is going to be around 7%. 7% with 90% LTV with a borrower who may or may not have been underwritten properly - If you asked any investor "would you invest in a debt fund that pays 7% net where the loans are 90% LTV" and people would say no way. 

As low-income owners with a keen entrepreneurial spirit, we balance W2 jobs with side hustles, such as selling custom t-shirts or baked goods.

One of the properties has about 50K in equity built up with a low interest rate on a 30yr loan. 

The current interest rates are more the norm and what we saw for the last 10 years was 'free' money due to the low interest rates.