What could I expect to pay in impact fees and to hook to city power/sewer etc?

Because if you pull it, it is a hard hit and depending on their goals in life (college, need student loans, new baby on the way, anticipating needing a new car), then a hard hit impacts them for a long time. 

Increasing interest rates will have an impact on selling prices and will likely hit the markets with the highest recent appreciation first and hardest. 

And waiting all those years, now factor in cap-x impact of that time eroding the savings.

We are looking for a letter of some sort explaining the process and benefits (better than raising rent, environmentally friendly, simple billing as payment adds to next rent rather than 3rd party) We would like to replace faucets/showers/toilets with low flow options to help curbs costs as well. 

Different markets experience yearly price growth that vary drastically; this may soften the impact of negative cash flow in markets were average values are extremely pricey compared to the national average. 

@Scott Passman The overall condition of the property (affecting future repairs) and the ongoing management (practices that generate cash flow) are going to have THE greatest impact on your overall long term performance. 

Won't be much of an impact as I initially quoted.

If you stick to SFR rentals with 3+ bedrooms it will probably have even less of an impact.

You can look at crime rates and other rental property within the area and see if that has any significant impact.