Any analog pin is fine for the voltage divider -- make sure the pin will never see more than 5V.
It's not at all clear what you mean by a "dump resistor". If you're referring to burning off power from the wind turbine when your batteries are full, then that resistance should be between the two wires of your generator (assuming a DC or single phase generator) and switched on and off with a mosfet or relay. A 1.7Mohm resistor is much too high for this, but unless you can provide more details as to the peak voltage and amperage of your wind turbine it's impossible to make a suggestion.