I'm considering the purchase of a backup power generator (we are in the land of the occasional tornado, hurricane and ice storm here and outages aren't uncommon).  

It is not uncommon for a good producer to make $1 million plus annually.

Also, I like your idea of student housing, there are two large universities in my area and it's not uncommon to see 5 students in one apartment paying $300+ rent each.

It is not uncommon for sellers to make the place looking appealing with stainless appliances and other eye catching amenities while the foundation and plumbing is a mess.  

This isn't uncommon, as most places don't cash flow.

I'm beginning to see it's not uncommon for some of the better cash flowing properties in DFW to be in areas where most (if not all) of the tenants mainly speak Spanish, so it's something one must become accustomed to dealing with in such areas.

Why would you want to buy just the buildings, this is super uncommon and very unlikely that even if technically possible that the seller would agree to it.Bottom line is you don't know what the mystery building is, it probably is not currently a livable unit.

If it's truly renovated and in great shape, it's not uncommon to see a lower expense ratio, BUT you have to verify that's the case.

@Matthew Rubsamen that response rate and results are not uncommon for yellow letters.  

It is not uncommon to have concerns.