Re: Uhura replacing McCoy/Bones?
Uhura 'lost out' because the character was written as a glorified extra from the start. Nothing more, nothing less. Nimoy and Shatner's egos had nothing to do with it.
Some say that BB-8 is made from his discarded helmets and that he once turned down a role as a Stormtrooper because it had too many lines.
All we know is, he's called The Stig