I like the cosmopolitan mix of names! However, it's worth remembering that EU4 doesn't have linked names like CK2 does, and there's several cognates in that list of monarch names. A "Pierre III" could be followed by "Petrus III" with that list, or "Ferdinandus II" followed by "Ferdinando II" and then "Ferdinand II". That's maybe a little wonky, and it'd be worth considering using only one name per set of cognates to avoid that sort of confusion. The mix of languages seems fine by me, but it's those cognate repeats that may cause trouble. 