Lightning Service component for picklist values

Question

I am trying to create a service component as illustrated in Trailhead

https://trailhead.salesforce.com/trails/lex_dev/projects/workshop-override-standard-action/steps/override_2

In this module it was given for one field which works beautifully. But let's say I have 5 different picklist fields on the Lightning component UI. So in that situation I am trying accomplish the concept but stuck in how to define the aura:attribute. If I define the way it is given here it is retrieving the values for the last called "v.picklistValues" for all of the fields.

    <***** Picklist Component******>
<aura:component controller="PickListController" access="global" description="PickListValues">
    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />
    <aura:attribute name="sObjectName" type="String" />
    <aura:attribute name="fieldName" type="String" />
    <aura:attribute name="picklistValues" type="Object" />
</aura:component>

****Picklist Controller****
({  
    doInit : function(component) {
        var action = component.get("c.getPickListValuesIntoList");
        action.setParams({
            objectType: component.get("v.sObjectName"),
            selectedField: component.get("v.fieldName")
        });
        action.setCallback(this, function(response) {
            var list = response.getReturnValue();
            component.set("v.picklistValues", list);
        })
        $A.enqueueAction(action);
    }
})
    <***** Parent Component calling Picklist component******>
<c:PicklistValues sObjectName="Executive_Snapshot__c" fieldName="Field1" picklistValues="{!v.picklistValues}" />
<c:PicklistValues sObjectName="Executive_Snapshot__c" fieldName="Field2" picklistValues="{!v.picklistValues}" />

Answer 1

When you add following code

<c:PicklistValues sObjectName="Opportunity" fieldName="StageName" picklistValues="{!v.picklistValues}" />

you are passing picklistValues attribute from parent component

<aura:attribute name="picklistValues" type="Object" /> 

so if you want to add another one add another parent component attribute and pass that as parameter

<aura:attribute name="secondpicklistValues" type="Object" />

your component will look like this

<aura:component >
        <aura:attribute name="picklistValues" type="Object" />
        <aura:attribute name="secondpicklistValues" type="Object" />
        <c:PicklistValues sObjectName="Executive_Snapshot__c" fieldName="Field1" picklistValues="{!v.picklistValues}" />
<c:PicklistValues sObjectName="Executive_Snapshot__c" fieldName="Field2" picklistValues="{!v.secondpicklistValues}" />
</aura:component>