This post is a compilation of various articles I've been reading on the development of Persona 5's UI Design. These articles are chosen for not being repetitive (unlike many other articles I've read), and provided interesting insight on the development of the game.
Pre-Release: Persona 5. By the Cutting Room Floor.
The Cutting Room Floor website itself is a godsend to those who wish to find information and behind the scenes artwork on games and other media. Found plenty of images that I couldn't find elsewhere. Wayback Machine Link.
The UI Design of Persona 5. By Jiaxin Wen.
One of the better posts that sing praises on Persona 5's UI. It is detailed, with interesting information relating to the UI itself and not any other aspects of the game. I learned a few things that I didn't know about UI design with this post. Wayback Machine Link.
The rest are self-explanatory:
Panel on the Concept and Development behind Persona 5's UI. By Reggy, PersonaCentral. Wayback Machine Link.
Persona 5 Developer Interview About UI Design, Sound Design, and Music. By Alex, PersonaCentral. Wayback Machine Link.
Atlus Reveals The Design Secrets Behind Persona 5's Distinctive UI (Wayback Machine Link). By Alistair Wong, Siliconera.