Florida homes are built on a slab so to install proper ac/heating you have to cut channels or venting channels in the concrete/floor you could come through the attic but that's not green and a professional would advise against it, is the ac your biggest desire to update?

When you change them, install the clean ones and take the dirty ones with you.  

some floor joists are saggingstoops need to be regroutedgrounds need to be cleaned upGFCI outlets need to be installed since it is currently old 2 wirepaint the outsideother than that, not much needed, just needs some elbow greasePlanning to do most of the work myself 

I just installed that in a kitchen and bath.

I'm getting a carpenter to do 10 cabinets/installed and painted white he's doing them for 700$ his work is amazing.

I don't know what the capital costs are for purchasing / installing laundry equipment (or having a coin operator provide all the equipment and charging lease / entering into a revenue share), but leasing an otherwise unused space for what may be considered below market rent is the closest thing that I've come across to "free money" in RE.

I have seen the $0 cap expense new building approach used before but I do not really understand it as the lifespan on everything starts depleting as soon as installed. 

The super yanked it out of theceiling and kept it in his custody.7) The bathroom "bathtub" is in deplorablecondition with the inner sliding screen door almost off itshinges and can fall on us while taking ashower. 8) The tap is moving around in the sink. 9) The bathroom doorknob was off its hinges but I got thatfixed... but now the door does not lock.10)TheA/C might have not been installed correctly, cold air seemsto flow through from outside constantly, it may pose to be a problem in the winters.11)Thewindow net is torn and patched with a piece ofsticker.

These are complex homes built to the California Building Standards Code that require installation and finishing to meet the regular California Building Code.Pedro's solution of trying to contact the manufacturers directlyThe manufacturers of modular homes (almost as a rule) don't sell directly to homeowners, so this is really a pointless loop that he is sending you on. 

We've also had the app randomly drop certain features (like the entire "spa" button on the app) after the main unit in the house was accidentally unplugged.....forcing us to uninstall and re-install the app while testy guests look over our shoulder.