The Forbes article said it is named after Star Wars space craft: http://www.forbes.com/sites/benkepes/2014/11/13/more-amazoni...

But I think it is simply named after the functional language feature. The core concept of this service is function.

I'm not sure what Nathan Marz's "Lambda Architecture" has anything to do with AWS Lambda, though

I don't think so. That is another naming abomination.