A confirmation field is a spry validation field.
to add spry field to your form, go to Insert -> Form -> Spry Validation confirm
In the spry settings, set it to use the Email Address element as the comparison.
to remove the security question validation, find the following 2 lines and delete them:
var sprytextfield10 = new Spry.Widget.ValidationTextField("sprytextfield10", "none", {validateOn:["blur"]});
$WAFV_Errors .= WAValidateLE(((isset($_POST["Security_question"]))?strtolower($_POST["Security_question"]):"") . "",((isset($_SESSION["random_answer"]))?strtolower($_SESSION["random_answer"]):"") . "",true,8);
These are not supported modifications to power store, if you require additional assistance in making these modifications, please sign up for a premiere support appointment.