GNB as one big reference.

[Halivel]

As everyone know from Gunbreaker description, their creators are Hrothgars, which is a first reference to FF8 (aside from the fact that we use gunblade, of course), where lion is a central figure:

- Squall's last name is Leonhart;
- His final weapon and limit break are called Lion Heart;
- He is Leo by zodiac;
- He wears pendant, ring and belt (not in original game in case with belt) with leo heads on this;
- Griever, the strongest GF, is a winged lion, also pictured on Squall's first weapon - Revolver (which we will get for collector edition).

But that's not all. Some skill titles that were catched during job overview are direct references as well:

No Mercy - Seifer's skill.
Demon Slice - Seifer's skill.
Rough Divide - Squall's skill.
Bloodfest - Seifer's skill.
Rough Divide & Blasted Zone - Squall's skills.
Continuation - this is probably "Renzokuken", will need to check the Japanese title of the skill. (UPD: checked. In Japanese version this skill still named "Continuation", written in katakana. However, "Renzokuken" itself has translation "Continuous Sword" and, same as 70 lvl ability, leads to few different skills after it, so it's still can be considered as Renzokuken).
Solid Barrel is also Squall's skill from "Dissidia Final Fantasy: Opera Omnia".

AF Gunblade name: Lion Heart (Personally surprised that they didn't keep it for last relic stage with original white&blue design but okay).

Also GNB battle pose seems to be based on Squall's victory pose but looks a little bit different so not sure if they are connected.

Update:
Royal Guard - Gladio's skill (?)
Female iddle stance - based on Lightning
Male iddle stance - based on Squall (Dissidia)

If you found some else references - share!