It might sound like a subtle difference, but keep in mind that the property has to appraise for that increased amount that the seller is crediting back to you. 

They could decide that they no longer want to allow owners to rent out their property or drastically increase the fees that could eat into your cash flow.

The interest rate might be higher, but perhaps the reduced expenses will offset some of that increase, or?  

Well...the Dayton Dragons baseball team has the most consistent sold out games of any sporting team in North America (startling fact), Warped Wing opened a second location, and a half dozen other breweries are now open in the city...Boston Stoker coffee is totally awesome and has several new locations (this is important because it's a key indicator for the successful revitalization of many cities...beer-food-coffee is key)...there is a river front development that is reminiscent of Columbus (which was awarded best on the country), there is big inner-city revitalization...I saw a developer by the name of Simms pre-sell 24 $500k "Brownstone" townhouses in the center of downtown (unheard of in Dayton)...there are 30 renovation projects going on downtown...and they now have a full time staff on the streets to keep the city clean...the population is on the increase for the first time since 1964....I mean this is pretty superficial, but it's every bit as important as economic indicators...there is a lot more to this...There are still "war zones" in abundance in Dayton and it's the Opiate Overdose capital of the USA...but getting better rapidly...just proceed with caution if you elect to invest there...a local subject matter expert is a must!

Not to mention the increasingly large families over the years.

I want to have a few multifamily properties to increase my income per door so I can hopefully retire much sooner than later.  

I do all of this for the long term gain (increasing rents and thus cashflow, along with appreciation).

Could probably increase the rent by $100 after the current leases are up.

Since then, I have fixed it up a bit (put in about 35K to increase rents).

There are credit forums with all of the tips needed to increase your score (keeping accounts open, increasing credit limits to decrease debt ratios, disputes, etc).