it depends on how the contract is drawn up, i don't think it's black and white across the board every single time for every single actor. del toro got $5 million when American gangster fell apart the first time around (when Antoine Fuqua was attached)...however it's not clear if that was going to be his entire salary or if it were a just a majority of what his salary was going to be had it got made.
not really, because at any given time an actor can charge whatever they want, whether you agree to pay it is another issue all together. they may charge you $10k more than their daily rate per day but then turn around and do it for $15k less than what they would normally work for when dealing with a studio or name director/producer/actor just off the fact there's a relationship/opportunity/advantage with that project that leads to something bigger. it all boils down to how well you can negotiate, how interested they are in the project and/or how bad they need the money. nothings ever set in stone and everything is always negotiable.
