The only ones here I agree with are with Everkeep and Otis parts which I picked up during the story. (Even though the Iifa Tree is referenced in text separately)
Zidane 'job' is a bit hit and mostly miss. You can argue that Reawaken is a Trance and that the dual-blade is a reference to Zidane but everything else is so far removed, there's no other aesthetic it takes from Zidane that comes directly from IX, Zidane is a Thief and doesn't have any aesthetics of a Viper that takes from its name if someone told me "I feel like Zidane when I play Viper!" I'd be stunned wondering why because outside of those two, and one of them might just be its own thing I don't see the resemblance.

I personally think Sphene is NOTHING like Garnet and I can't for the life of me see that from Krile at all even personality wise nor the journey they take.
Wuk Lamat isn't similar to Zidane at all (and I am not going to humour the her being a Hrothgar is reference to Zidane at all, not to be rude sorry.)- Zidane is competent well rounded individual that people come to for advice and offers it and naturally from the start fits into the leader role even with resistance he gets from Steiner and later Garnet due to his own actions. You could argue that they go out their way to help people but that's a such a generic trait of a good-willed protagonist but swap the roles of Wuk Lamat and Zidane in their respective games and it'd be a completely different story, I don't see them being similar at all.

I would love to hear the Necron part of the of Queen Eternal's theme if you don't mind just telling me what section of their song plays if you will, IX is my favourite FF game I'd love to hear it (and can't believe I would have missed it, unless it's incredibly subtle).

But again I feel that the while there are similarities the major themes of the story are just so mismatched that DT heavily pushes forward the community/culture as opposed to the theme of IX even the character journey don't match for any character that's supposedly a parallel to their IX counterpart.
It's like people think that "This is DT re-telling the story of XI" when really they using material in a way that fans of IX can enjoy it and those who never played IX would be oblivious to it even being a reference and not be lost.

The only time I thought this went a bit too far was in EW's .1-.4 patches.
Though that might be a detriment to be playing the game before, I am not sure how it'd affect people who haven't played IV but I do know people who have not touched IX(or interested FF in general) and they didn't know any better for the IX references in this game.