You only need to add the users list to the module used to create the filter not the final output.
Create a module dimensioned only by user and two line items, one dimensioned by customer list and the other by sub brand list. This is your filter selector.
Create a module dimensioned by customer and sub brand containing the users list, create three line items; customer filter, sub brand filter and final filter dimension these as boolean. This is the filter module. Reference the filter selector to determine if the dimensions equal those selected.
Customer Filter = IF ISBLANK(FilterSelector.Customer) THEN TRUE ELSE Item(CustomerList) = FilterSelector.Customer
Sub brand Filter = IF ISBLANK(FilterSelector.Sub) THEN TRUE ELSE Item(SubBrandList) = FilterSelector.Sub Brand
Final Filter = Customer Filter AND Sub Brand Filter
Apply the final filter line item as the filter criteria to you output module. You do not need to add users to this module as you can select 'Current User,' when defining the filter criteria.