Is that an estimate based on them knowing the area or do they need to physically be inside to look?

The address needs to be a physical address where notices can be served.  

When I had concerns he was able to either give me a physical report, i.e. smells, carpet condition etc., or leverage the video feed, i.e. any polarized plugs, better view of the roof, etc.Additionally, all the documents were signed electronically.

I'm not sure the legality of that provision - don't believe that all HOA covenants are legal; some have never been tested in court or even vetted by a decent attorney - so that would be a legal question: who is liable (beyond the tenant) for physical/financial damages caused by an individual you did not place? 

The tech was physically there and if the door were open he'd come in to repair the issue.

As far as the process goes, I would recommend starting with J Scott's book on estimating rehab costs: https://www.biggerpockets.com/store/flipping-estimating-physical

The property also had a rather bad reputation in Wausau, so finding decent tenants once the physical property was improved would have been a challenge as well. 

Also, look at economic vacancy, not just physical vacancy.

Not everyone will agree with this recommendation, but I physically go visit the neighborhoods where I invest.  

The app, background check, and getting security deposit & first month rent does not require you to be physically there.