I think your analysis might be mistake. Although it is hard to find pictures from exactly the right angle, i have been playing in photoshop and I have just about convinced myself that ETNZ has more rocker. It's hard to be sure because of 2 factors. First, there are the issues of the angle of the phots, plus the ETNZ boat is healing. Second, the ETNZ rocker is very unusual, having the concave sections in the bow and transom. This completely changes the way the rocker looks.
First impressions of the cat's hulls and platform are that it looks heavier that Team NZ's first cat, NZL2, has low freeboard forward of the wingsail, and a lot of rocker in the hulls, looking to generate lift from their daggerboards.
I suspect that the ETNZ rocker is about tacking and gybing. When they go 2 hulled, the extra bouyancy and the rocker profile will dramtically reduce the waterline and this will mean the boat will spin fast.On one hull, the extra weigh it has to carry (full weight of the boat) plus the rig loads will mean that the waterline will be full length. The issue is whether there is a penalty for the concave rocker but I bet the other design teams will be crunching numbers on this.
As for the weight, sorry, but I really don't know how you can say that from those photos, and I doubt there will be any actual difference in this respect. I suspect you are being fooled by the wrapping of the structure.
My initial impression is that the ETNZ boat is all functionality over looks while the Artemis boat looks very "Gucci". It's slick and has got some great detailing that's visible even in these pictures. We have no idea if it is the right shape, but I get the impression that it will set the standard in terms of detailing.