If any costs go up, developer eats it.

Given that the property was worth $390K in its current condition, I saw an opportunity to make the numbers work while keeping my upfront costs low.Instead of increasing my cash offer, I negotiated a $25K down payment with the seller carrying the balance for two years through owner financing.

You have to include the cost of your time and the work, especially on a "scary house" is daunting indeed. 

In one of my markets assessments are performed every 3 years, and the cost of 3rd party appeals will cost 30% of 1 year savings. 

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

If they don't show up, projects get very delayed and become unprofitable, even costly.

More work, more time but you can take advantage of a nice cost segregation / bonus depreciationThis is the truth! 

Insurance-  replacement costs.  

You need the backup option in case the mid-term rental market changes.Minimizing turn costs and downtime is critical.

Most PM software allows late fees to be charged.Ours allows us to absorb the cost of tenants paying electronically thru the software - it usually wants to charge tenants, but we want them to pay electronically.We manually charge tenants a Processing Fee for mailing in their rent, a slightly lower Processing Fee for depositing to our bank.Your success will depend on the Class of your tenants.