The "high appreciation rates" you mention should be verified with recent data and be specific to the neighborhoods you're targeting.

As you mention, if you are using hard money yes you are paying more in interest and if you hvae the cash I would recommend using cash over hard money due to the high interest rate that you are paying.

Like @John Underwood mentioned, you need to set the expectation of a 5 star review.We're very specific on our messaging automation. 

Maryland’s DLLR site you mentioned is definitely a step in the right direction.

When you mentioned you did your homework on the turnkey property, if that were the case you would have had a really good idea what the property was worth before you offered on it (of course sparing the occasional rogue appraiser, which may be what happened to you... idk) and certainly before the appraisal.

Having said that, rents go up over time and as you mentioned tenants are paying down the mortgage (with more going to principal over time). 

It likely means you have that amount of coverage when caused by another peril and as mentioned it's typically a significantly lower limit than other coverage amounts.If a pipe bursts, it will likely be covered. 

As mentioned above do not focus on this number, at all. 

Like Thomas mentioned, leveraging your personal residence carries higher risk.

One option I haven't noticed being mentioned is to auction it.