G1-3 Fomorian does seem to be Irish yeah, though the issue is that they seemed to have translated Irish words into Korean, then tried to translate them back into English. The result is a lot of words "read" correct but are spelled wrong. A very modern example is Cravan, which is craobhán. Ironically, all items in Korea have English translations which is how I'm aware of this because the Cravan Liquid is instead Sap of Craobhán. But not all weird words are Irish, as is the example of Bondi. Bondi is a Chinese loan word in Korean, and even worse an unusual variant of that loan word too. It gets worse depending on which Mabinogi generation you look at though; Blago was a fun bit of work for example (that I'm not even convinced 100% of). Another editor has a page of work (not all of it is perfect but its a good start) here https://wiki.mabinogiworld.com/view/User:KaedeKit/Pronounce. If you look through that there are a lot of languages that any one word could be from, including: Welsh, Scottish, Irish, Hebrew, Latin (in general), Manx, Cornish, Breton (on rare occasions), Greek, Danish, French, German, Russian, Italian (on less rare occasions or because of themed regions). Iria is even more interesting because it includes more Latin, German, Quechuan, Paiute, and other Native American words. All first translated into Korean, and then retranslated into English.
Ah sorry. Trying to figure out the meaning of old (likely rushed) translations often leads to a lot of questions and I push for a lot of clarity before cementing something as trivia. Wiki editors have been trying to figure out a bunch of stuff behind the scenes (in example, we recently found out the meaning of the word 'Bondi'; tldr: it is an obscure word that means 'originally' in Korean) and I worry that sometimes misconceptions get carried onwards forever (there was an infamous 'name' for the dark sun in the shadow realm that only the wiki ever offered as fact). For what its worth, I've done a ton of looking into the names for the -ark gods and Aton. All I've ever found was that Shemini might be the Hebrew word for 8. I obviously don't have enough to claim that though so I've kept it off of the wiki for now (I had a lot of false positives on Bondi until we found what it meant, so had I acted on any false positive I might not've found the real trivia; speaking of I should add that fact properly to some page soon).