I would skip the fruit or go minimal on it, myself. Sumac would probably give a nice pink colour and tart citric acid character to an otherwise plain mead, but I tend to think it would make a mead with fruit a little too tart unless you went easy on the fruit and sumac, or if you had something pretty tannic in there or a lot of sweetness to balance it. Sumac is pretty tart stuff. It would be a good acidifier, say, in place of an acid blend, but I'd be careful mixing it with acidic fruits. And wormwood is bitter, so it might bring it along, but tastes bloody awful, IMHO.