This is just getting me more hyped for the game.
And by the way, why do the Aliens have to remain just an easter egg? Its not like its anymore ridiculous than super mutants, ghouls, talking mole rats, talking spore plants, an intelligent radscorpion, Crazy homicidal presidents that want to destroy the survivors of the war that aren't part of the Enclave despite the mutations being relatively benign and the people (except the Shi) are technically citizens of America, The Vault Experiment and its use of people that could have been used to repopulate America for stupid social experiments instead, etc.
Tell me exactly how aliens are any more ridiculous than what I just typed.
TL;DR: There's a lot of crazy shit in the Fallout universe, Aliens isn't that stupid of a idea.
Willing to make friends with Atheists, Buddhists, Communists, Islamics etc etc as long as they have reasonable morals. Jehovah's Witnesses and Scientologists excluded.