I will be spending about 3 months in Ireland and am wondering if my Moto g4 Plus will support an international (specifically IRE) sim card. If not, will the WiFi only plan work in Ireland?
Your Moto G4 Plus does support use of an international SIM. You might find this of interest: International Travel with a Republic Phone. Prepaid cards from Tesco (sort of a British-Irish Walmart) are popular choices for traveler’s to Ireland: Bill Pay | Prepay | SIM | Tesco Mobile.