We have two main issues that I will outline below: HeatingTwo heating systems in the home.

I read this as someone using a short-term lens to focus on a long-term issue. 

We went from buying light rehabs to buying major foundation and mold issues to make numbers work until even that did not work anymore.

Quote from @Jeff Roth: Hi Lina from Texas-Congratulations on your interest in investing in mid-term rentals and you are wondering how and where to get started.I get this question frequently from investors.Sometimes and investor is looking to keep their property cashflow positive as insurance and taxes have squeezed cashflow by turning units into mid-term or short-term rentals.First off, ideally, the property will cashflow as a long-term rental should something disrupt the mid-term rental model.You will also want to have the property be near where there would be a demand for mid-term rentals (hospitals, universities, research centers).Monthly rents for mid-term rentals are about 20% (+/-) higher than unfurnished similar long-term rentals.There are property managers that will manage mid-term rentals for you and I always advise my clients to use property managers to keep their investment as passive as possible and for compliance issues related to Fair Housing Laws and local regulations.To Your Success! 

Each week, I analyze the MLS, exploring cities and towns across South Florida to identify areas favorable (or not) to short-term rentals.

The inspection showed more issues than we expected but the seller wasn't willing to negotiate so we cancelled in the due diligence period.

You may run into issues with re-tenanting and it may take longer than you expect or cost more.  

After that, if issue is addressed but ground floor tenants keep complaining - remind them that common noises are expected when living in an apartment. 

Now I can see some builders having an issue with comps.. but other than that its crazy to take these funds as income and then pay tax and plow it right back in.. 

Having a rock solid SOW can prevent many of the issues that arise during any project.