Morning Kinderchicklets!
The easiest way to tell them apart when they are all by themselves in the nestbox is by size - Ivy is much smaller than Princess (all boy peregrines are smaller than girl peregrines). Now if you can see their heads, Ivy has more black on his head, makes it look a bit like he's where a black touque. Princess has whiter "cheeks". So, when you are looking at one of the bird's head, look at the way the black comes down on the sides of their face - Princess has much more white than Ivy does.
If they come a little closer to the camera, you can look for black speckles on Princess' chest - Ivy doesn't have any speckles. And if you can see their feet, look for the bands on their legs. Ivy has a black band on one leg and a silver band on the other leg. Princess has a black and green band on one leg and the other band looks kind of pink.
Hope this helps you out! I know you will all be expert at identifying the peregrines in no time!
The Peregrine Chick
