That wikipedia article is pretty clear that it is a myth and there is no genetic evidence of shipwrecked Spanish sailors having children.
Yes. There is an Iberian connection that explains Irish folks with dark features, but that would be from Neolithic farmers migrating there 5000 years earlier.
And you see a similar connection in he other direction in northwestern Spain. Regions with redheads and bagpipes. It's not a majority, but you can see it from families tracking their roots to that area from 700+ years.