The Irish shouldn't have gallowglass, they didn't exist until the high middle ages. Nor should they have 'dartmen', which would just be about any Gaelic unit anyway. Near all Gaelic soldiers carried darts or a heavy throwing spear. Having 'dartmen' is redundant. The Scots also have no concept of a difference between 'highalnders' and 'lowlanders' yet; that came about from Norman influences later on. Really, Scots and Irish in the period you've selected would share most of the same units, except maybe a Pict unit of some kind. Niether would have very advanced archers, the Irish particularly. They used militia levies of archers, but rarely anything more, except mercenaries from Wales. Scots were fond of crossbows though, when they came about. The Welsh shouldn't share units with either of them, and the Scots and Irish should both have pretty much the same units, except as otherwise stated. Both would have pikemen, they used clubs often (probably some type of militia or light infantry), both were fond of spears, and of mid-length swords, as well as axes, throwing spears (heavier and larger than javelins), etc. The only appropriate 'highlander' would be a type of Pict warband probably, since the only remaining cultural Picts would be from the more isolated northern hilly regions toward the end of the period (and eventually even they'd be assimilated). Additionally, Scots and Irish also had 'wood' roads, which were more permanent highways, as well as the occassional 'raised' road (like the Kilburn road or the Oahgan nGall path), though mud paths may fit that role, but it sounds rather crude.