A thought: Lunasa, Samhain, and Bealtaine (I may be spelling these wrong) are all named after their associated holidays (on the first day of the month) of Lughnasadh, Samhain, and Beltane. However, these three holidays were part of a series of four, the other being Imbolc (february 1st). The word Feabhra seems so similar to its english counterpart I imagine it must be borrowed, and it is the only one bearing no resemblance to its holiday. Does anyone know the story behind this?
I read that the root for February comes from the word februra which is a piece of goat skin the Romans slapped each other with during Lupercalia to bless people with either love or a child.