There is a cash machine but it only dispenses US dollars. The casino will advance you dollars against your seapass account which you can use for tips if required but you will get euros from ATMs ashore if you run short.
Yes there are, $5 each time you use them,& not a good rate either. They are there to make money for RCI. Use the ones ashore.
Yes there is an ATM on board and it charges $5 every time you use it. Best to use the local ATMs ashore. Far better exchange rate on shore at a proper bank.