On that note... how would one go about becoming a deity in this setting? Will it just be a matter of getting enough people to worship her as one, or is there something more to it?
Well, no one starts
as demigod (which is divine rank 0). But following guideline there are three ways;
1) Get enough followers to pray and recognize you as deity (potent spellcasters more easily garner favor so sublime chord is good way to do so). Numbers were insane though but followers can help spread word and thus expand your flock (epic leadership and legendary commander approach close to numbers you need).
2) Steal divine energies and imbue them on yourself (Cyric did this on Time of Troubles in Forgotten Realms by siphoning energies of God of Murder; Bhaal, albeit aided by Mask who was short sword at the time).
3) A divine entity empowers you directly and sponsors you to divinity.
Anycase paragon favored soul would work very well (cleric needs power directly from a god or believe in philosophy where as favored soul has innate divine battery, but cleric as class got more PrC options and domains give nice options also), I did some homebrew changes for favored soul so it's more interesting.