Using promises to GET and process data
I think the preferred way to handle async on the server in Meteor is to use fiber aware async functions, e.g. use the http Meteor package which gives you fiber aware "sync" style calls on the server (you write it like a sync call but it does not block the thread) and standard async callback signature on the client.

Also, I am not sure about using futures on the client, is there even a fibers environment running on the client?  Instead, I think you just pass a standard callback to Meteor.call to handle the results of the method.