I found an interesting site for comparing names. I can't trace the exact source(s) used for all four names, but the references given for the entire site may prove useful (and impossible to scroll through, admittedly).
Adam: Originally from the Hebrew אדם, "'adam", meaning "man".
Eve: Originally from the Hebrew חַוָּה, "chawwah", derived from חוה,"chawah", ...
First, note that the first known mention of Ask and Embla is in the Völuspá, in the Poetic Edda:
Then from the throng | did three come forth,
From the home of the gods, | the mighty and gracious;
Two without fate | on the land they found,
Ask and Embla, | empty of might.
Soul they had not, | sense they had not,
Heat nor motion, | nor goodly ...
That claim according to which there was a Sabine month called Flusalis can be found in a footnote of William Warde Fowler's The Roman festivals of the period of the Republic; an introduction to the study of the religion of the Romans (p.92). Here is the complete footnote:
Steuding in Myth. Lex. s. v. Flora. There was a Sabine month Flusalis (Momms. Chron. ...
It is used in both these ways.
Among the Ancient Greeks and Romans, just as in almost any other culture or language in the world, especially in the neighbourhood of the Mediterranean Basin, if a descriptive title or nickname gets enough usage, not surprisingly, it coagulates into something that, for all intents and purposes, is "a proper name."
I was taught that there is a relationship between φοῖβος (brightness) and φόβος (fear). The idea is that Apollo's radiance is not gentle, but glaring like the sun.
Apollo is not typically portrayed a "warm, fuzzy" character, but as uncompromising, like truth, for which he is a patron. His brightness is fearsome, deadly, and unerring, like his arrows.