I don't think that rudder will be set back far enough at 2" and 4" seems like too much. The aquajet rudder titled

Product ID: ose-bj10-bj11
Rudder with standoff bracket
$8.99
is set back 2 1/2" and seems to be perfect for the application.
As far as props go you will have to do some experimenting. Start off with the stock prop and see how she runs and what the temps are like, Then prop up from there. Turn fins are not necessary but can help the ride of the boat out alot and they can be had pretty cheap.