Easy way of seeing if something works: TRY IT!
<Style TargetType="Button">
<Setter Property="Content">
<Setter.Value>
<MultiBinding Converter="{StaticResource OmgLolzConverter}">
<Binding Path="One" Converter="{StaticResource CakeConverter}"/>
<Binding Path="Two" Converter="{StaticResource CakeConverter}"/>
</MultiBinding>
</Setter.Value>
</Setter>
</Style>
Works fine.