LJoshi,
You should be able to get the DisplayName in a Store using the ObjectID from the lookback API like this:
Ext.create('Rally.data.wsapi.Store', {
model: 'user',
autoLoad: true,
listeners: {
load: this._onDataLoaded,
scope: this
},
filters: [{property:'ObjectID',operator:'=',value:<UserObjectID>}],
fetch: ['UserName', 'DisplayName'],
limit: Infinity,
sorters: [{property: 'UserName',direction: 'ASC'}]
});
There is also an example with a different workflow which uses Lookback API to fetch the first revision of an Artifact then uses the ObjectID from the Lookback API data to get the UserName available here:
GitHub - markwilliams970/Artifacts-ByCreator-Lookback
I hope that helps.
Michael