I doubt they had that in mind when they published the book, and that was just a few days ago!
But yeah, they might decide to try and sweep it under the carpet in the end.
And we might all be better off.
I mean, did they really need to briefly kill Tidus off in order to write something about his existence being precarious? He was made of Pyreflies to begin with, after all. Isn't that enough? Couldn't they find a better way to kill him? Are they not bothered at all by the whole "Tidus's suddenly head flies off in front of Yuna" thing? Are they so desperate to replicate other people's successes (Madoka Magica? NieR?) that they don't see or care about how much a tonal shift that represents for that franchise? Is that really something you want to cover in-between games? Isn't that death a bit too major an event for a bridge novel (that might not even leave Japan)? And two freaking days after the good ending? Seriously? How did that sound like a good idea? It's really some geostigma-level BS, right there.
And holy shit at what they did to Yuna's character... We spend hours playing a game where she's absolutely inconsolable over Tidus's absence, she gets a break at the eleventh hour (a bona fide deus ex machina, really)... and now, we find out that she immediately started bitching? Tidus is basically acting like an overjoyed puppy, and Yuna's all "oh, it's like he doesn't understand me at all", "now he's getting on my nerves", "how childish of him", etc. And Tidus has to keep freaking apologizing. Gah.
Look, if you want to write something about how there's no "they lived happily ever after" or ask "would the Prince and the Princess really get along? do they really have much in common after all?", fine, go ahead (although you might be overestimating the demand for gritty "this is real life, and it mostly sucks" in something called "Final Fantasy"), but you have Yuna act like that just a few hours in? Seriously? Again, how did that sound like a good idea?
X-2's perfect ending felt like a surreal, almost innocent, romantic fairy tale. So when you undermine it with all this silliness, it suggests that they neither understand nor appreciate what they created before. With the novel, they stumble into metachlorians territory attempting to deconstruct the nature of Tidus' existence. We really don't need to know anymore, really.
MY PERFECT ENDING - a fan-fiction by PedroPanache
Yuna : Look, I'm really sorry I brought you back, but, hey, it's not you, it's me. I think we should break up. I thought I wanted that holiday romance thing we had, but to be honest Tidus, you're really boring. And your head explodes. It actually explodes. That's a dealbreaker, right there.
Tidus : This is the exact fucking opposite of "cherish me, Yuna!". You're not cherishing me, Yuna,
Yuna : Yeeeahhh, that whole "cherish me" thing is kind of needy, and, look, the sex is really, really weird. Not that I'm complaining, but technically you're kind of dead...and I really want children and you're shooting blank pyrefiles. The truth is I didn't think any of this through when I brought you back. We really should break up.
Tidus : But...but...what if I disappear?
Yuna : Well, there's always that swimming pool the Fayth built you.
Tidus : Oh yeah, it's the one you dragged me away from when you decided to bring me back.
Yuna : Oh, right, sorry, I'm so sorry. You know maybe we can do the whole friends with benefits thing. I get horny, I summon you. We have sex. I send you. That could work.
Tidus : I..just....TWO DAYS YUNA! OUR RELATIONSHIP FELL APART AFTER TWO DAYS!! HEY, WAIT WHAT ARE YOU DOING?
Yuna : I'm not doing anything.
Tidus : You are, you...you're...YOU'RE SENDING ME...YOU'RE ACTUALLY TRYING TO SEND ME!!
Yuna : Brother got me pregnant!
Tidus.. MOTHERFUC........