Personally, fuscia doesn't strike me as a color that would look good on many people (I sure can't wear it!), but if it looks good on all your girls, sounds good.
As for the MOH vs the other BMs, mine wore the same gown, which was indigo with a navy sash. If you want her to wear a different color, perhaps she could wear the opposite. For example, if your BMs are wearing fuscia with pink sashes, your MOH could wear pink with a fuscia sash. Just a thought. If you want her to be different, I'd go with a color that compliments. Or a different dress in the same color.
My MOH will be wearing the same color as the rest of the girls. However, she'll have a fancier bouquet. In my sisters wedding, she bought us our accessories and I had similar, but fancier ones as well so I am thinking I may do that too.