Okay, here is my proposal for the remaining islands:
I agree, specially because France, now, has a proper african base to reach Zenobia. (... and Mauretana shall rule South Atlantic!)
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Behold, gentlemen, our creation: The Carta Magna Mundi Veteris*!
(*The great map of the Old World, if my latin is not that bad)
edit: oh, with Mauretanan St. Helena, Ascension and a large piece of African coast, I think it makes more sense to have their (ex-)colonies in South America.
And, well Zenobia Austral and Zenobia Boreal sound rather neat, as it's probable they would call all the lands they found in the west the same - maybe the italian guy was named Bartolomeo Morello, and one/some/many nations are named after him?
Or the French and Castillians called it Zenobia Boreal, however the Anglish , at first, thought they found a new land, and called it Morelia after, uhn, the explorer Francis Moore?