Now if the circuit breakers are down there you could have an issue. 

Another new draw for SE Austin / Bastrop is the Circuit of the Americas, which just announced a new NASCAR race series and the creation of a water park and other entertainment. 

Some of the breakers have old rust and minor corrosion, as well as some of the wire ends.

Since this is an investment for you, I think lean towards deal breaker than maker.

Get on few local Wholesalers Cash Buyers List - Make sure to vet the wholesalers carefully as wholesaler are known for inflating After Repair Value (ARV) which can be a major deal breaker.

This has been preliminary investigated by electrical engineers who said there was a short circuit on one of the interior house circuit(s) to the stucco (which is under the siding) lath/mesh.

Treated for bugs, replaced the interior and exterior "Zinsco" Breaker and service panels ($10,500), remodeled 2 bathrooms, replaced 3 of 5 water heaters, smoke detectors, added kitchen and bathroom GFCIs, 1 AC unit, 1 new dryer, replaced 2 windows, repaired several more windows.

It does cash flow better then a SFH, you are correct.In my case:- it had to be re-zoned as MF with the city- an additional post office address had to setup (1A, 2B)- natural gas line was split and 2nd meter was added- 2nd electrical meter was added outside- 2nd electrical circuit breaker panel was added in the basement next to the other panel, and all the wiring for upstairs unit was moved into it- city does not allow for a split up of incoming water to add 2nd meter so both units have to share it.

Should that be a deal breaker or is there a way to get certainty their credit is improving and they will make on time payments?

The first-panel label states that the breaker panel is rated 40 circuits.