Luachar appears to be Rath Luachar, which according to the Ossianic Cycle of tales is in Connacht. Rath is the Gaelic word for fort. There's also a reference to Luachar in The Book of Invasions: Badb and Macha and Anand, of whom are the Paps of Anu in Luachar were the three daughters of Ernmas the she-farmer. The Paps of Anu are in Killarney, Co. Kerry. I don't think it's the same Luachar, though, because the Ossianic tales refer to the place the crane bag is kept as Rath Luachar, which is said to be in Connacht. I just thought it was interesting. Firvolgian is another name for the Fir Bolg, which has also been equated with the Belgae. In Irish mythology, the Fir Bolg were the fourth wave of inhabitants of Ireland. And the Tua-de-Danans would be the Tuatha Dé Danann, the fifth group of inhabitants of Ireland.