AKA it is a way to access some of the money you've put into your home while also making sure you can still afford your mortgage payments and other debts.You will need a renter in place as rental income is apart of the calculations when underwriting these loans in addition to the other factors you mentioned like monthly housing expenses (PITIA: principle, interest, taxes, insurance, assocaited fees ARV, debt outstanding.

I bought a 110k property in cash last March. It currently rents out to tenants.What’s the earliest I take out the equity and invest again?

Projected income minus projected expenses etc.

Don’t get scammed by some on line service where they paid $100 for the letter.

I've included an example below to help illustrate this.So different lenders have different rates (which do vary even for DSCR loans) but these are factors they all consider.See example below:DSCR < 1Principal + Interest = $1,700Taxes = $350, Insurance = $100, Association Dues = $50Total PITIA = $2200Rent = $2000DSCR = Rent/PITIA = 2000/2200 = 0.91Since the DSCR is 0.91, we know the expenses are greater than the income of the property.DSCR >1Principal + Interest = $1,500Taxes = $250, Insurance = $100, Association Dues = $25Total PITIA = $1875 Rent = $2300DSCR = Rent/PITIA = 2300/1875 = 1.23DSCR lenders generally let you vest either individually or as an LLC.

Who paid the $20,000 original cost of the home? 

Utilities (only power paid by owner) - $120/Mo?

Assuming the property was paid off at the time of death you're wife basically inherited $225k. 

We have never paid our construction company for services.

Land seems expensive, especially compared to Northern NM which is another market I am considering.