I know this thread is almost a year old, but I'd thought I'd chime in anyway.
Standard duncan singlecoils are south polarity, dimarzios are north. Wind directions are the same, but this doesn't really matter as far as compatibility since you can just swap the hot and ground leads when soldering to change the wind direction.
So for a duncan and dimarzio singlecoil pups to be humcancelling and in phase both need to be standard (according to each brand's specs), but when wiring it up you need to swap the hot and ground on one of the pickups.
In your case, if you have a duncan in the bridge and dimarzios in the middle and neck, to be humcancelling in pos 2 and 4 you'll need a standard true velvet in the middle, and a rwrp true velvet in the neck, and the hot and ground with both pickups will need to be soldered the other way around (as in, if the duncan is wired white-hot, black-ground, the dimarzios will need to be the other way around: black-hot, white-ground)