What's the etymology of "Oscar"?

Question

Wiktionary gives this:

Irish Osgar, from os (“deer”) + cara (“friend”) ; resuscitated by James Mcpherson in The Works of Ossian (1765). Napoleon, an admirer of the Ossianic poems, chose it for his godson Oscar Bernadotte, who became a king of Sweden.

It can also be explained by Old English ōs (“god”) and gār (“spear”) (see Oswald, Osborn, Oswid, Osric, Oslak).

While Wikipedia states that:

The name is derived from two elements in Irish: the first, os, means "deer"; the second element, cara, means "friend". The name is borne by a character in Irish mythology—Oscar, grandson of Fionn Mac Cumhail. The name was popularised in the 18th century by James Macpherson, creator of "Ossianic poetry". Today the name is associated with Scandinavia because Napoleon was an admirer of Macpherson's work and gave the name to his godson, Oscar Bernadotte, who later became Oscar I, King of Sweden.1

The given name Oscar is not to be confused with the Old English Ōsgār, which is of an entirely different origin (from two Old English elements meaning "god" and "spear").2

So the question is: What is the real origin of "Oscar", Irish or OE?

Answer 1

From BehindTheName.com:

Possibly means "deer lover", derived from Gaelic os "deer" and cara "lover". Alternatively, it may derive from the Old English name OSGAR or its Old Norse cognate ÁSGEIRR, which may have been brought to Ireland by Viking invaders and settlers. In Irish legend Oscar was the son of the poet Oisín and the grandson of the hero Fionn mac Cumhail.

My read is that we don't know with any certainty the origin of the name "Oscar", but we do have a few viable alternatives.

Answer 2

Oscar is of Gaelic origin. Åskar is Scandinavian for Lightning but despite the fact that Sweden and Norway have had kings called Oskar, the name is even regarded there as having a Gaelic source:

http://spa.118100.se/namn/42892