The Octonaut

I mean these were quite literally nomadic cow-herding tribes acting independently and frequently fighting each other even across the sea so “imperial” is a bit rich.

Probably a much better comparison to the Vikings who did something similar: individual gangs raided British coastlines and then eventually began to settle there. Except the Gaels/Scotii did it during Roman times, the Vikings later.

Both are Irish. Ó means “of” or “from”, and sometimes is interpreted as a looser association with a clann (family).

Scottish is Irish. Gaelic peoples settled Western Scotland from Ireland. Literally the word “Scot” used to mean “Irish”.