No, the Macho Brace won't give any extra EVs to Pokemon that hold an EXP Share. It would gain the amount of EVs that match the defeated Pokemon's EV yeild and the Macho Brace would only work for the Pokemon that does not hold the EXP Share.
These items' effects are doubled by the effect of Pokérus. For example, if a Chikorita with Pokérus that holds a Power Lens defeats a Haunter, that Chikorita would gain 12 EV points in Special Attack. Two would be from defeating the Haunter, four would come from the Power Lens, and the remaining six would be from the Pokérus's doubling effect. However, a Pokémon holding the Exp. Share will not gain any of these boosts, and unless already infected with Pokérus, will only receive the base EV yield of the defeated Pokémon.