I am getting into private lending slowly but surely. I'm really a newbie. I'm discussing with a rehabber team about a loan, they're local, and I like them and am willing to meet them more than halfway to earn their bu...

Your girlfriend seems to have a big heart, but she is naive to the dangers of bad tenants.

(Again, I know I'm being overly simplistic and generalizing, which is always dangerous).

I could avoid having to put money on deposit to the utility company if I let them run my credit (meaning I would be personally responsible for the bill)  --  I am okay with that as there is no danger of the bill not being paid by the SDIRA but wondering if this item would be a violation. 

It is a situation fraught with danger of causing rifts in friendships and creating stress in the family ties that bind.  

No opinion on your location, but in general:Older homes:Better framing/worse foundations/mechanical systems in need of serious update (electrical, plumbing, heating)/area either more run down or more expensive (already gentrified)/more compartmentalized layout (no "open floor plan")/more dangerous material (asbestos, lead paint, knob & tube)/more termite damage/cheaperNewer homes: more or less the opposite. 

What, I think, is important to comprehend is that the question is highly dangerous and misleading.

Is the property in a dangerous/undesirable area?

But it is very dangerous to compare the USA to nations like New Zealand and Australia etc. because our markets are driven by a shortage of available land.

In exchange for fewer headaches (no tenants, toilets, or termites to worry about), you don't get to use as much leverage (debt financing) or get the juicier tax benefits of directly owning real estate.