We are hoping by joining BiggerPockets we can get help from like-minded persons and communicate for help.

Hiring an extra person does not seem like the right step.

@Neil SmithPull a list from the auditor of what you're looking to call, load it into a dialer, call the numbers and ask to speak with the owner (their first name) - Introduce yourself by being personable (Who you are(first and last name - age/background), where you're from(local guy), and get straight to the point - why you want to buy and if they're interested in hearing an offer on their property - it's like a quick handshake over the phone. 

One maintenance person can stop by 4 properties in one day to take care of issues.

Personally, I prefer purchasing a property that is not new construction.

My personal favorite is "The Unofficial Guide to Real Estate Investing" by Spencer Strauss.

Reasonable accommodation does not extend to allowing safety issues to go unresolved or personal property to be damaged. 

Though a cost seg study doesn't increase your chance of audit, if you happen to go to audit it would be very tough to defend as a lay person. 

So if I buy a replacement property worth $500k, can I use proceeds from the personal residence half to cover the other $150k?

You can look it up yourself, but maybe just maybe the person that installed the tile didn’t take that precaution and now the install failed.