If I were investing in this property I would want to know if the units were large enough and what improvements need to be made to meet CHA standards.

, and how much cash or OPM do you have for repairs/improvements after you buy it?

Purchase price was $500k, improvements were $300k, and list price will be $2MM.

Can you sell a property and use the proceeds under a 1031 to make an improvement to another property that you own?

Save back the rest of your money for repairs and improvements.

I understand what this "rule of thumb" is trying to accomplish, but it's a rule I wouldn't use. 

What special rules do I need to follow (e.g. proper number and placement of smoke detectors and carbon monoxide detectors) that might apply to a rental property that don't apply to a primary residence, or where can I find these rules?

As I'm sure you know, property isn't too expensive, it's possible to find a good number of properties in good areas that satisfy the 1% rule or greater, and given how many good universities and companies are in the area, I don't see the city declining anytime soon. 

Have you ever purchased a mobile home and wanted to improve the property only to learn there were things that you missed prior to closing that you should have known?

What can I do to improve my changes of selling near ARV?