[SalesForce] Translation Workbench Override Managed Package Custom Field Label

My current workaround for this is to add a server side action (custom labels work in apex) that would return a map of all the custom labels used in the component and then set it as an attribute of type "Map". (You need to reference all custom labels anyway in order to include them in a managed package)

bottleneck: You have to make sure you load labels before doing anything else. If you have nested structure of your components and you load labels only once in the root component -> you have to manage loading of custom labels to insure the labels attribute is accessed only when it's populated.

Apex controller:

@AuraEnabled
public static Map<String,String> getCustomLabelMap(){
    Map<String,String> customLabelMap = new Map<String, String>();
    customLabelMap.put('MyCustomLabel1',Label.MyCustomLabel1);
    customLabelMap.put('MyCustomLabel2',Label.MyCustomLabel2);
    return customLabelMap;
}

Lightning Component:

<aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
<aura:attribute name="LABEL" type="Map" access="private"/>

<lightning:button label="{!v.LABEL.MyCustomLabel1}" onclick="{!c.myFunction}" />

Lightning Component Controller:

({
    doInit: function (component, event, helper) {
        var action = component.get("c.getCustomLabelMap");
        action.setCallback(this, function (response) {
                var LABEL = response.getReturnValue();
                component.set("v.LABEL",LABEL);
        });
        $A.enqueueAction(action);
    },
    myFunction: function () {
        //myFunction
    }
})

Object's translations are retrieved only for object's custom metadata, which is included into package.xml For example, if package xml contains only one custom field and one page layout, then translation will be returned for that field only

For example:

<?xml version="1.0" encoding="UTF-8"?>
<Package xmlns="http://soap.sforce.com/2006/04/metadata">
    <types>
        <members>Sample_Object__c-es_CO</members>
        <name>CustomObjectTranslation</name>
    </types>
    <types>
        <members>Sample_Object__c.Sample_Field__c</members>
        <name>CustomField</name>
    </types>
    <version>37.0</version>
</Package>

That will return Sample_Field__c translation as result.

In case if entire sObject needs to be translated, then package.xml should be like next:

<?xml version="1.0" encoding="UTF-8"?>
<Package xmlns="http://soap.sforce.com/2006/04/metadata">
    <types>
        <members>Sample_Object__c-es_CO</members>
        <name>CustomObjectTranslation</name>
    </types>
    <types>
        <members>Sample_Object__c</members>
        <name>CustomObject</name>
    </types>
    <version>37.0</version>
</Package>

P.S. Very interesting behaviour, found by me: In case if package.xml contains custom object from managed package, and also page layout from managed package, together with non-English language, may cause translation for page layout name returned without prefix . For example:

<layouts>
    <layout>Sample Object Layout</layout>
    <sections>
        <label><!-- Address Information --></label>
        ...
    </sections>
    ...
</layouts> 

Problem is that it may fail on deployment. Fix is easy -- add prefix manually before deployment:

<layouts>
    <layout>MY_AMAZING_PACKAGE__Sample Object Layout</layout>
    <sections>
        <label><!-- Address Information --></label>
        ...
    </sections>
    ...
</layouts>