It does! It makes for a more effective disguise as well, since the vocal differences will make the Three Lights and Star Lights seem like different people.
I'm curious how their male forms will sound. I have an idea of how Taiki will sound (I'm guessing it'll be close to Erika's Kurapika voice), but no clue on Melissa as Seiya or Sarah as Yaten.
I was thrown off by that as well. But according to Erika Harlatcher, they'll sound more masculine in their male forms. Apparently they decided to make the gender differences more pronounced in the dub.
Have you watched the Kiznavier dub yet? If you haven't heard already, Crunchyroll is making the English dub available of it for free on their website. I just finished the first episode and I'm already impressed by the dub.
Also, have you been able to check out any of the Clear Card dub yet?