First, I think it's good to compel you (judging by your answer, and the other previous conversations) to recognize that the relationships in FFXIII (as in other FF games as well), have a deeper quality than just a singular dynamic. Meaning, I wouldn't just say Fang/Vanille, to simply describe them, are just family. Their closeness is described and shown to have more justice than that—not to only simply abide by that straight to the point meaning. But, that description works harmoniously and reasonably in conjunction with their interactions, dialogue, characterizations, and background with one another in the series. You would be able to draw other respective conclusions with characters such as Caius/Yeul, Noel/Yeul, Lightning/Serah, etc.
The problem is, you're ultimately trying to define them by subjectively fabricated implications of subtext, rather than the subtext that accommodates what the stories context holds within itself—the overall presentation of the story and characters together. There isn't a single thing you've said that is guided outside of your own, personal interpretation.
If there is a conclusion to be drawn, it has to be fully, without personal interpretation, approached from the context, and THEN, we can see a subtext to certain aspects. Yet, the understanding of said subtext is the most cogent when it doesn't forego the meaning the context has already set in place. This helps keep it as impartial as possible, and even though subtext is something inevitably of one's interpretation, we know it can be approached objectively. (the basis of rhetorical analysis for literature).
Based on the context of Fang/Vanille's relationship in all FFXIII material, all your examples don't necessarily represent an underlying romance as much as you've concluded it to be. And even further, your points don't support the more effective, clear subtext that relies more on the overall storytelling.
No one would have thought they were anything but a couple of Fang had been a man.
Again, that argument isn't valid. If Fang was created as a man as first intended, there is no say in what his personality would be like, not to mention, what ultimately his relationship with Vanille would have been. It doesn't matter what inspiration their overall characters came from. Fang was created as a female with her particular personality as a representation of what the original concept of Lightning was suppose to be.
Am I to assume you believe that if Fang was male, he would have also looked at Vanille's brand the same way a female Fang did when they reunited? Of course, personality is still a factor there, and how SE would want to handle that. However, when you look at the female Fang's own personality, weighed to everything else in context of the story, characterization, interaction, etc.—even that action itself shows a close bond, that also, reasonably lends itself more to that familial connection and background they share. There isn't any romantically implied instances that support otherwise, and her possibly being male means nothing to their bond.
The way she embraces her in that scene looks platonic to you? Again, they sleep together in the same bed.
That embrace? Sure.
I'm not sure how you believe only those who are romantic would do such a thing to one another, but I will fully say that isn't the case. This especially, again, when you understand the closeness they share stemming from their history with one another. This applies to a hug, or even when holding each other's hands in the way it has been done. Also, if you understood the characterization of Fang and Vanille, including their background, them sleeping in the same bed makes sense. That sounds like something they would do considering they were orphans together at a communal village in Oerba. Again, that doesn't necessarily mean romance when you see and understand what kind of close relationship they have as a result of befriending each other there when they lost every other family member they had.
How would that be any different from family members sleeping in the same bed? Especially ones who have been through what they have been? Ones who have shown to have a close dynamic and bond the way they do?
Fang talks about Vanille the same way Snow talks about Serah. There's the Yin Yang symbolism that is usually reserved for couple (Square used it for Tidus and Yuna as well, for example). You can't tell me the subtext isn't there. Doesn't mean it's 100% confirmed, but it's not wild speculation based on nothing.
I can see how you make that parallel. But, the parallel between Fang/Vanille actually stems even further than those two characters. Other than Snow/Serah, this includes Lightning/Serah, Caius/Noel/Yeul, Sazh/Dahj, etc. They all use the same language, all have similar mindset and heart for a pattern that is heavily emphasized as a common (if not the most imperative) theme throughout FFXIII's narrative: strong conviction for those they love.
In such depth, Fang/Vanille are more comparable to Caius/Noel/Yeul, as both groupings have showed signs of a strong enough conviction that, they'd be willing to destroy the entire world for that person. Simply comparing them to Serah/Snow is clearly not enough to provide any implied or recognizable romantic notion between the characters as this involves a multitude of themes/characters in the story.
Also, if you wanted to talk about dialogue specifically, you should pay more attention to how they address one another in the series and the dynamic of their conversations (Chapter 11 of FFXIII—when they're at Grand Pulse, is a great example)
When all you're doing is defining the subtext by your own narrative, it doesn't always present something substantial to the characters. Most subtext is something that is inherently personal view anyway, but even that can be objectively weighed instead. Arguably, Fang/Vanille's relationship isn't something that takes a complete analysis anyway. There are plenty of subtexts that have been presented upfront in stories, and some, you don't need to delve too deeply to see it's fruition in context. This happens in plenty of games.
For example: if Aqua had not mentioned Terra/Ven had a brotherly relationship, would it still be in question what their relationship was? How about for Aqua and Ven? Would everything that has been shown surrounding those characters in the context of the franchise, from their actions, to their words, their conviction—would one still adamantly believe Aqua sees Ventus as a romantic partner rather than a younger sibling/best friend?
If someone does, subtext be damned. Well, at least if you're parading it as something outside of personal want/ideas.
While a relationship is ultimately deepened by understanding a story in its entirety, there are some things that use that depth to present things at a rather face value within context. These things don't necessarily need an official confirmation spoken by a character or the creator to grasp an understanding of.
One of many examples in FFXIII: taking in the scene where Fang and Vanille reunite is something that is conducive of their background and characterization, which in turn, reasonably emits to the familial/sisterly bond that can be understood there. Look at their interaction during and even after she checks her brand. Think of their closeness presented throughout the story and take into consideration their history with one another. This does not clearly indicate romance, but rather, the familial bond that is emphasized more in dialogue and actions throughout the story. An internal, personal subtext isn't really needed to understand this—the overall story, the scene itself, shows enough. The storytelling alone does the hard work, and that work is immense and special on its own grounds.
Fang/Vanille's relationship is presented well, and when you take the time to understand it in context, rather than your own subtext, you'd see romance is not a guiding point of their closeness. I know we're talking about finding meaning under that presentation, but even the ever possible romantic notion there isn't that implicit of itself, and certainly not within the context of their characterization and dynamic in the story.
Also, don't get me wrong, I still understand where you're come from. Of course, people are basing it on something (though we know, some shipped pairings don't), it all stems from somewhere. Signs of affection or declaration of importance is something that hopeless romantics (such as myself) would cling to when looking at possible couple pairings to filter through. Their closeness is, really, a reasonable ground for people to speculate on. But, there is a certain point you have to understand that your speculation, especially over personally created subtext, doesn't necessarily define that couple's dynamic or what's really happening there truly. Feel free to be all about it though, but just know that's what you, and other like-minded individuals, solely desire, and isn't necessarily by the weight of the characterization in any material.