Your cheery picking quotes from
the site. And not grabbing the full definition. Your definition is literally every character death ever. Here's what it means in more than one sentence:
Aerith and Luna do not die for the SOLE PURPOSE of affecting another character. Their deaths had larger story implications and reasons for their deaths. Character's being affected by their deaths is an obvious byproduct.
Fridging and having deaths having larger implications are not mutually exclusive things, good person. Not even close. Writers tend to justify fridging with the excuses you've used, including "oh yeah, them being alive would get in the way of the villain's plans", despite that being doubly true of the main protagonist. In fact, you neglect that had Aerith not died, as a plot device, that just furthers the story whilst serving as a motivational tool for the male hero, she wouldn't have been able to bolster lifestream, which further screwed Sephiroth's plot over, thus contradicting his motive to kill her. The fact that women as heroines are disproportionately killed as a plot device is what forced the coining of the term in the first place.
I can candidly say i haven't played ffxv, but it seems you have, so let me ask you:
Did Luna actually have agency? Did any of her actions aside from dying move the plot along? Could she be replaced with a potato for most of her screen time? Did she largely exist as a motive for the guy to do hero things? The fact that her death was narratively rationalised doesn't negate that she was fridged. The fact that she may have displayed a modicum of agency for two seconds doesn't overshadow the rest. Only you can answer these since you've played the game.
Going back and forh about the semantics of frodging without adressing it at it's core concept and how it is applied is a bit dissengenuous. It seems to me that this Luna had an item for Noctis, then gives the thing to him, then dies. If her death has more of a narrative point than her even being alive, there seems to be a huge issue with her development too. Staying in the confines of one video or two from Anita and a paragraph isn't all-encompassing of how the trope has been applied in a multitude of ways.
People often falsely equate men dying with women being fridged, despite the popsided and disproportionate rate at which women are killed off for the sale of plot or male development. It isn't the same dynamic, nor does it carry the same context. In a medium where what, 10 percent of the leads are women, there's a huge paradigm not being discussed here. For every dead guy, there are a thousand male heroes with agency and plot power. We can't say the same for the other party.