I believe that an overall improvement in the complex and the common areas will be a better place to invest than just one or two of the apartments.  

But don't assume the contract you are signing has the same terms as the commonly used one.

1.when selling a 10-year old unit in a common interest development such as condominiums,stock cooperatives, or planned developments,which form must be used?

And yes you can 1031 a "share" of property as long as you mean a tenant in common % ownership of a piece of property.  

There should be hard-wired smoke/fire alarms in all units and common areas.

Have a situation where a husband and wife owned a house via tenants in common. 

https://www.biggerpockets.com/files/category/contr...You can also use google and type in Northwest Multiple Listing Source Purchase and Sale Contract and find the one commonly used by many agents.  

This was common many years ago, but if you ultimately want to go with a traditional underwriter (freddie, fannie, etc) then you can get into trouble if the seller (landlord) has been giving you money (rent) toward your downpayment.

As for the wooden buildings, the legislation aims to target "soft story" buildings, commonly those with garages or commercial buildings on the first floor.  

The janitor expense seems interesting as well as I am not sure who charges $33 per month to clean a common area...Here is what I would guess the building really looks like:Gross income minus 10% vacancy factor= $148770NOI using the 50% rule= $74,385True cap rate then would be 11.4.