My partner was getting it and we are told we have to pay for an inspection.  

I recently hired a property manager to handle almost everything, like the rental license, lead inspection, and repairs.

Did you have a home inspection and was this mentioned?

Pre-inspection, it appears to be a solid opportunity.

The Earnest Money Deposit (EMD) is refundable during the Due Diligence (inspection) period, and goes hard at the expiration of the DD period.

Here’s a quick checklist to cover your bases:Property Condition: Get a thorough inspection to assess major items like the roof, foundation, and HVAC—this helps you plan for any big repairs.Financials: Account for all costs, including taxes, insurance, maintenance, and property management fees if applicable.

Unfortunately being a rookie I went with an inspector that came from a company that had a solid website and the inspection failed to spot many items.

Strategy is long term hold.Question - Apart from getting inspections done by a quality inspections company, what other items do I need to verify or consider as part of due diligence, before closing or in order to decide Go-No-Go?

You can do as little as 0% down and maybe even get money back at closing if you can implement seller credits into your offer during the inspection period or prior to going in contract. 

It lost a significant amount of granules from home inspection and multiple roofers.