Hi Pip, thanks for the question.
Some of what you discuss is covered under the Kingdom of the Isles. Wikitree has, unfortunately become a little imprecise which I will look to resolve in the coming days.
The title: Mor, Ri Innse Gall, King of the Hebrides, King of the Isles consists of some duplication and an error. "Mor" or more correctly mór is Gaelic for large and not in the title. Ri (or Righ) is Gaelic for King or Lord, Innse Gal is Gaelic for Island of the foreigners (Vikings) and refers to the Hebrides. King of the Hebrides is the same, but he actually only held part of the Hebrides, and King of the Isles refers to the Norwegain Kingdom of the Isles (which includes much of the west coast of Scotland) which was independent of Scotland and held to the Norwegian Crown during the period in question. This Kingdom varied in size during the period and, by the time of Somerled, had been divided into two, with Somerled, late in life, holding the southern isles. He was also Lord of Argyll, a title he held to the Scottish Crown.
The last question; not sure and likely needs to change. In the Irish Annals (thus in Irish Gaelic) he appears as Somhairlidh mac Gillebride mhic Gilledomnán.
I can resolve the profile..