The broken tiles are availble to replace,no problem.^_^
but we and your also have to consider the potential damage.
If to replace,there are only 2pieces to deliver by express,it's very easy to broke again owing to its special size.
the broken situation is easier more damage than the current.
About the broken,there are professional stone gluings for sealing the marble.after gluing and thenpolished.the seal is not obivous.
The installion worker should know this point,you could require them to make it.
Waiting for your further updates to go ahead.
Best Regards,