Interesting project. There might be some skin on this deal, but I'm not sure how much. Here's what I see:
If you're putting down nearly 40%, you should get a lower interest rate in today's environment.
Is this owner financing interest only? With a 30 year amortization that includes principal payments, I'm looking at $1,962 per month.
You need to factor in a vacancy rate. It might be 100% occupied right now, but you can't assume that vacancy will stay 100% once you take over. The current vacancy rate in Houston is 11%, so that right there will make a big impact on your proforma cash flow projections, basically pushing you down to break-even status before raising rents.
It's hard to analyze expenses without knowing more, but it seems a little light. Are you sure you have enough for repairs? I'm looking at about $20K a year just for property taxes, insurance, and management fees. Then with an old 8 unit building, you probably have to pay for trash, lawncare, and utilities that can't be split out like water, or possibly electric? So add that in and then you need money for repairs and unit make readies.
$485,000 may be TOO MUCH for this property, if the net income isn't there to support the valuation.
I don't know what the seller means by owner-financing to avoid reporting capital gains taxes. Even with owner financing, I would still want title insurance and closing at a title company with an updated survey. You just never know if the current owner's ex-wife has community property rights to the place or some easement crosses under a building, etc., and that means the title company reports the sale to the IRS and owner will be paying capital gains.