In the very first Japanese release of the game, at the bottom of the well in Corel Prison, a rare debug enemy known as "Test 0" that was accidentally left in the game on its initial release can be randomly encountered. This encounter does not require cheats or hacks to occur, although GameShark codes can be used to access every other debug enemy battle in the game. This battle was removed from all future releases of the game. "The Completely Unauthorized Final Fantasy VII Ultimate Guide" by Versus Books, released in 1997, features an entry on this enemy (note that the HP listing in the guide scan is incorrect; Test 0 has 30000 HP).

Final Fantasy VII Rebirth nods back to this oversight by making Test 0 a legitimate optional encounter in the Beast Battleground. The nature of its presence in the original game is referenced in the enemy's bestiary entry, which describes it as "A test subject that managed to escape Shinra's R&D Division due to a developer's oversight."

In an interview with the game's music supervisor Keiji Kawamori published on the PlayStation.Blog on September 14, 2023, he was asked what he could reveal about the soundtrack and music for the game. He responded that because the game's world is much larger than Final Fantasy VII Remake, the team made a variety of new music to go alongside it and also expanded the variety of musical genres used, so he thought there would be a lot to enjoy. They also made many re-arrangements of classic tracks from the original Final Fantasy VII, and Kawamori hoped fans would enjoy comparing both iterations of the same song to see what's the difference. He cited the Release Date Announcement trailer's music being a re-arrangement of the Final Fantasy VII main theme as a battle music track as an example of this to give players a taste of the direction the team chose to take in Final Fantasy VII Rebirth.

In an interview with the game's creative director/artist Tetsuya Nomura published on Dengeki Online on September 21, 2023, he revealed that the late voice actor Keiji Fujiwara would still be the voice of Reno for the Japanese dub of the game. Fujiwara passed away from cancer on April 12, 2020, at the age of 55, just two days after the release of Final Fantasy VII Remake. The news of his death came shortly before the recording sessions for FFVII Rebirth commenced, leaving the developers unable to replace him immediately. Because of this, Nomura asked the scenario team to let him use past recordings of Fujiwara’s voice for Reno in Rebirth, and "they made the necessary adjustments." As a result of this, Reno's screentime in the game had been reduced to account for his death, and after apologizing to fans both domestic and international, Nomura revealed that the third part of the Final Fantasy VII Remake series will introduce a new Japanese voice actor for the role of Reno and that the character's presence will increase.

In April 2023, Final Fantasy VII Rebirth's lead battle programmer Satoru Koyama discussed the challenges he aimed to tackle when working on the game, with his main aspiration being to enhance the capabilities of AI characters. He emphasized the desire to create an AI capable of juggling a variety of techniques and magic, going beyond the limitations of Final Fantasy VII Remake's combat system. He said his goal was to surpass the Gambit System introduced in Final Fantasy XII, which allowed players to set commands and actions based on specific conditions, providing a wealth of strategic options.

In an interview with the game's co-director/designer/programmer Naoki Hamaguchi published in The Washington Post on July 2nd, 2021, he reflected on the evolution of Final Fantasy VII Remake's battle system, which drew inspiration from the original game's Active Time Battle (ATB) system. Hamaguchi expressed satisfaction with its current form "in which the strategic element of the command-based battle from the original co-exists with the real-time, action-oriented battle". Additionally, the "Intermission" episode featured in FFVII Remake Intergrade introduced combo moves where Yuffie and Sonon team up, which Hamaguchi stated he wanted to try leveraging along with other elements from "Intermission" as he worked on what would become Final Fantasy VII Rebirth.