C area - c construction - aren’t these 2 red flags enough ?

Contacting your insurance carrier is a great first step.

Regarding Liability Insurance, check with your homeowners carrier. 

Again beef up with umbrella and require tenants to all carrier a renters policy with a specified amount of liability and make sure you are added to their policy as an additional interest.If you are buying a BRRRR property you are going to need to start with a builders risk policy during the rehab and then convert the policy to a landlord policy once you have tenants in the home.If you own multiple 1-4 unit properties or a mix of residential and commercial you can bundle all of it into a commercial package.The other type of policy you can buy if you own the property free and clear is an Actual Cash Policy.

Whatever the actual uncured default rate is, the lack of transparency, to me, is a yellow flag.

According to PennDOT, a guy with a regular license can legally operate a vehicle of up to 26,000 lbs.Assuming the law and its limits stay exactly the same and don't change to benefit the changing interests of very wealthy people and industries historically flush with cash while sticking it further to the weak, poor, and helpless (which of course never happens in America the Beautiful), that means that Pennsylvania cargo carriers will in the near future be able to pay an unskilled worker less than 1/4 of the going rate to take on reliably more than 1/3 of the typical truck load handled by a well-paid and experienced trucker.So I am rather certain that one of the first things that is going to happen is that we're going to see more smaller trucks controlled by autonomous technology with minimally paid people behind the wheel just watching the technology do the work (perhaps while they do a second unskilled job on their tablets) on all roads moving more and more cargo, while there will be a decrease of larger load carriers with expensive drivers on roads that allow trucking traffic.So if there's a road that goes over a bridge that typically has a lot of commercial tractor-trailers going over it in and out of a big shopping development primarily accessible by the bridge, I'd expect to see fewer large trucks on it and faster pickup on the smaller trucks going over it, which would increases the rate of traffic and would likely improve congestion along that artery, thus making rental properties on the less desirable side of this bridge more easily accessible by people who who don't want to pay out the nose for rental properties on the more desirable side of this bridge.

Without debt I don't see huge disadvantages to owning inside an LLC, just check with your hazard insurance carrier.  

A non-working HVAC discovered during the inspection is a big red flag.

I have handed out business cards to multiple different people including UPS FedEx and mail carrier drivers.

Any red flags that you can see in hindsight?