I reckon it will cost 500mill, less heroes than endgame and infinity wars, but now everyone knows they can command bigger salaries!
1-1.5 billion for sure, as both the previous films looks good (F4 and Thunderbolts). I suspect one more film will come out early next year before Doomsday anyway.
Like others I think getting RDJ to play a new character will feel a bit hollow, but fans will probably love it
rp2000