Frequency doesn't come into it for normal electrical devices, as long as the voltage matches it will be fine. 50/60hz differences only really affect display equipment.
you can't
Yes, no problem.
220v 50Hz
nothing
There should be no problem at all.
220V , 50Hz
220V 50Hz
Yes no problem the transformer should run a little cooler as well.
More than likely yes it will work just fine.
No, 120 v is not enough.
No
The voltage used in Ireland is 220V AC, at 50Hz.