The roof is in need of some repair (~$2000), but should probably be replaced entirely in the 3-5 year range for roughly $21000 (huge roof).

I know in the town where our apartment building is, the above doesn't require a permit, but if I was going to replace windows, then a permit would be required.Also, our electrician told me that licensing is not required to perform any work that isn't going to be closed up behind a wall. 

As Boomers age, Millennials are more than replacing them in terms of buying power.

I am interested in  replacing our current household income from our own business with profits from real estate.

Also, since most properties in Las Vegas are still selling below replacement cost, prices in the few surrounding cities are not significantly less than metro Las Vegas so commuting does not make sense. 

I put in my leases that tenants must replace light bulbs.

In 1031 exchange which is under my personal name, can I close my replacement property under my Single member LLC?

I don't know anything about that area specifically, but I think an architect and engineer just has to sign off on the design for it to be accepted by local building codes.

Given the chance, I replace it...it might mean that I don't get a record profit on the project (or any at all), but I sleep well knowing I've done the best I can.That being said, 15k for a re-wire and panel upgrade it pretty steep for one apartment.  

If it will need to be replaced in next 3 years, replace it now.