You're right. Though it's still a matter of debate as to it's canonicity within each individual instalment that it borrows from, Dissidia is itself canon and a full Final Fantasy - as it were.
Regarding the subject of "nakama" though, it should come as no surprise that the word has multiple interpretations based on the context.
For instance, in Dissidia 012 Cloud asks Cosmos to "heal my nakama" in reference to Tifa. It wasn't a moment where he was sitting down trying to discuss the minutia of his relationship with Tifa. He wasn't even talking to Tifa, but to Cosmos. One can suggest perhaps he was too embarrassed to say "lover" or "girlfriend" or the like, but it was hardly a moment in which the relationship between Cloud and Tifa is made or broken either way.
Now, when Cloud calls
Aerith the same thing, the context is entirely different. We've just had the Sector 5 dream date, an entire recreation of the same date in the same location as Aerith had in Crisis Core, but with Zack. Her behaviour comes across as weird to Cloud, who comments as much on a number of occasions.
Events don't play out as they did in Crisis Core - one will note however that the game goes along with the illusion, classifying this as a "Zack chapter," his face appearing on the save file and the entire scene skipped if one switches Zack off from the menu - and the date doesn't work, Cloud can't be made into Zack no matter how much she tries.
Finally, in the church, Cloud calls her a nakama - or, in high affection, says they'll hang out together again - to which Aerith is disappointed and leads to her admitting that she is unsure of her feelings for Cloud. It's liking, for sure, but it's not quite like liking after all.
The context of this nakama is radically different. Now Cloud is addressing Aerith directly after an entire chapter seemingly dedicated to providing closure for the two, and in particular, Aerith. This sequence serves to define Aerith's relationship with Cloud as having gone from strangers to solid friends in a few short weeks. In this context, the word nakama was used deliberately by the devs to enhance that definition.
Whereas in the case of Dissidia the word nakama was not the focus of the scene, here the word lies at the heart of what the entire scene is about - thus it works and ultimately remains the same in both high and low affections, the narrative flows well into either so long as one remembers that this is definitively Aerith's moment of emotional closure, just as it's about to physically be so also.
) join the club.
