Pick two names you love equally.
Don't have them starting with the same letter or rhyming.
It's OK if one is one syllable and the other 2, but try to have a similar vibe.
Check that diminutives won't rhyme or sound funny. (Matilda and Camilla fine but Tilly & Milly not, Thomas and Jeremiah fine but Tom & Jerry, Myles and Frasier - people will think Niles and Frasier )
Name T1 the name that comes alphabetically last, so that T2 can be first on lists not always second.
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Both your name lists are from names that are currently popular and not overused, and I like that they are not frilly and long. I only like Rosa from your girls list and Jasper from the boys.
Eden - seems a bit too current. Unisex. Not keen
Cora - apple corer
Rosa - nice
Nora - prefer Norah
Of those, Rosa and Norah/Cora but I'd pick Anna, Astrid or Nina instead of Nora
Myles - Miles is nice but I don't like Myles
Jonah - and the Whale. Bad luck association
Flynn - ok, prefer Finn
Jasper - ok
Frasier - I like Fraser but Frasier was a tv comedy.
Of those Miles and Flynn, or Miles and Finn, or Miles and Fraser.