Sorry for the late reply, just saw this comment now when digging through the Blog posts, anyways, here's my opinion: I doubt they would, it would be cool if they, but really not likely. There's just too many dark themes and violence in FMA for that stuff to reach the Network unless they'd probably censor or edit a lot of the content in both shows. Besides, FMA's target audience was for Teens/Tweens, not children. I doubt that children would be able to understand a lot of things in the shows, with the talks of Religion and Alchemy and all. Someone made a video even poking at a "What if FMA was on 4Kids." While more humorous than anything, it's still rather true.
Fullmetal Magician Episode 1 (If 4kids got FMA Brotherhood)
If FMA was put onto 4Kids.
It only covers Brotherhood. Check out GoatJesus's other videos on FMA as well, they're really good reviews (watch out for Spoilers though. He warns the viewer every video of Spoilers before he starts.) Also, I think you mean 4Kids, Fox Kids has been dead since 2002.