PMed him. I'll get on the Scots soon if it'll help. I think that's the best alternative, but I'd have a few Irish regional units;

Galloglaidh; they were still used, but they were technically mercenaries, so it might be wiser to just have them as mercs, and they did work for others but the Irish. Also, they favored a two-handed long axe, not a greatsword, in most cases. They used the Sparth axe (a 6 foot pole with an axehead on it), and dressed in chain armor and iron helmets. They originated in around 1200 AD as the need for heavy infantry climbed faster than Irish kings could train their own. They hired these mercenaries from the Hebrides. The name itself means 'foreign warrior'

Kernbannal; spearmen/lochaber axe men, they worked four months out of the year, and traded off, they were peasants, they wore padded coats or leather, and marched in a formation akin to a phalanx (similar to what Scottish pikemen did, but with shorter weapons, so not as good); Irish light infantry

Omacach; swordsmen with flintlocks, they'd fire a shot and charge, the earlier version, the Cleighcach (Cleighnaght), are just swordsmen, these would be like Irish medium infantrymen, with leather brigadines and large wood shields, with longswords, or Irish-hilt swords.

Lewnaght; THESE are two-handed swordsmen, not the Galloglaidh; Lewnaght used the forerunner to the 'slopping quillons' style sword of the Scots; the lewing sword is bigger, longer blade, rounded off tip (it's too long to thrust with properly), and a 'four-hand' grip, a massive grip that accomodated numerous hand positions to utilize the very complicated martial art used for the lewing sword; these swords date as early as the 4th century, and were used by the Irish into the Victorian conquests, and one even showed up during the Anglo-Irish war in the early 1900s; Brian Boru's sword was a lewing sword. Very heavy infantry, in chain armor and iron helmets

Hobilar; Irish medium-to-heavy infantry. Irish hobilar were different from English or French Hobilar; they were nobles or wealthy aristocrats; they wore good quality chain armor, iron helmets, swords or hand axes, Irish lances (which are used in an overhand fashion), and javelins, and rode small ponies (larger horses have trouble on Irish soil over long distances)

Taghhoba; later hobilar, wore padding instead of chain, iron helmets, and used rifles and longswords or Irish sabres; essentially the same as hobilar, but with a better ranged attack, and poorer armor

There are a ton others, but this gives, I think, a fair grab bag of Irish soldiers for regional units; three types of infantry, and two types of cavalry.