When you start combat, after determining surprise and establishing positions; you roll for initiative. At this point, do all combatants have a reaction or bonus action even if they are not first?
For example: "X" is talking to "Y" when they break out in a fight. The fight begins with X and Y standing adjacent to one another. X is first in the initiative order and decides to move away then attack. Does Y have the ability to use a reaction (Attack of Opportunity)? If yes, can he use another reaction after his turn?
In a sense I am asking if reactions can be used on a per round basis or specific to the character.
If it were a per round basis, Y could perform an Attack of opportunity and on his turn will not be able to ready an action.
If it is specific, he won't be able to perform an Attack of Opportunity on X's turn, but would be able to if he moves so he is adjacent to X and X moves away on his turn.
Or can Y use a reaction to attack, then on his turn, gains back a reaction?