Since both Persona 6 and Ace Attorney 7 refuse to be announced, or even teased, I tried to come up with a nice crossover.

For starters, Adachi could be replaced by Gumshoe. Adachi acting like the clumsy, naive detective in public, and Dojima screaming at him is similar to Edgeworth and Gumshoe's relationship, in a way. However, Gumshoe would never kill anyone, so we need a new villain for Persona 4. And that's where Matt Engarde comes up. Mind you, this has spoilers for Justice For All. Matt Engarde's manipulative, two-faced celebrity persona would fit P4's setting. The party would enter the final dungeon and then his meek and clueless facade drops and he reveals a scarred face and ruthless personality. Instead of hiring DeKiller, he manipulated Namatame to do his bidding. Also, as he did with Maya, he would kidnap Nanako to use her against the party and Dojima.

In Persona 5, Redd White would easily fit as one of the many Palace bosses. The arrogant, flamboyant and self-centered businessman, who makes a living out of blackmailing judges and high-ranking government officials. Most likely, he would be backing Shido with his information. Anyway, he'd be a prime target for the Phantom Thieves. Damon Gant could also take the role of SIU Director, which would tie with Sae's plot very nicely. Gant would be subtly manipulating Sae into upholding her twisted idea of justice. Then there's Mimi Miney which whole storyline is similar (and better) than Sumire's. Finally, there's Luke Atmey and MaskDeMasque but that's a big can of worms.