I think u made a smallllll mistake :)
use like this
<li ng-repeat="cust in Customer | filter: myfilters | orderBy: 'Name'">{{cust.Name}}</li>
please put the Name as a string in orderBy as 'Name'
UPDATED FIDDLE
in order to filter by those two drop downs you need two separate filters, in angular its so simple as below line,
<li ng-repeat="cust in Customer | filter:selectedValue | filter:CityselectedValue | orderBy: 'Name'">
first it filter in selectedValue which is the first dropdown, and the second filter filters the results according to second dropdown.
UPDATED FIDDLE
more specifically use can use like this,
first dropdown
<select ng-model="selectedValue.Name" n..
second dropdown
<select ng-model="selectedValue.City" ng-opti..
in ng-repeat
<li ng-repeat="cust in Customer | filter:selectedValue | orderBy: 'Name'">
FIDDLE