If I may ressurrect this thread... as a fanboy, of course.
Here are some of my guesses:
Phoenix Wright - ENFx, 6w7 (I'm unsure... Nick seems kind of neurotic and cautious - at least outside the courtroom - to be an ENFP...)
Mia Fey - xNFJ, 1w2 (Her advice seems more Fe-ish than Te-ish, and she did a lot of stuff - especially in her early days - based on her own feelings about things)
Maya Fey - ExFP, 7(w8?) (she could be an ESFP, I think)
Miles Edgeworth - ISTJ, 1w9 (his way of thinking is quite linear and thorough, and his values resemble typical SJ ones)
Larry Butz - ESFP, 7w6
Winston Payne - xSTJ, 6w5
The Judge - ESxJ, 1w2? (Has the "goofy" tert Ne thing going on, IMO - I'm familiar with it)
April May - xSFP, 9w8?
Redd White - ESTJ, 3w2 or 8w7?
Marvin Grossberg - ISFJ?, 6w7?
Wendy Oldbag - ESxJ?, either an 8w7 moving toward 2 or a 2 moving toward 8
Dee Vasquez - IxTJ, 8w9?
Will Powers - ISFJ?, 9w1?
Dick Gumshoe - ESFJ, 6w7
Manfred von Karma - ESTJ, 1w2
Lotta Hart - ESFP?, 7w8
Lana Skye - IxTJ, 1w2 or maybe 6w5
Ema Skye - INTP?, 5w6?
Damon Gant - ENFJ or ENTP, 8w9
Jake Marshall - ISTP?, 8w9
Mike Meekins - xSFJ, 6w7
Maggey Byrde - ISFJ?, 6w7 (and with good reason, poor girl)
Franziska von Karma - ESTJ, 8w7 or maybe 3w4
Morgan Fey - ISFJ, 2w3
Pearl Fey - ExFJ, 2w1?
Ini Miney - ISFP, 9w1?
Regina Berry - IxFP, 9w8?
Acro - ISFP, 9w1?
Max Galactica - ESFJ?, 3w2
Matt Engarde - ESTP, 3w2?
Adrian Andrews - ISFJ, 6w5
Shelly de Killer - ISTJ, 1w9
Dahlia Hawthorne - IxFP, 9w8
Ron DeLite - INFP?, 6w7
Desireé DeLite - ESFP, 7w8
Luke Atmey - ENTP, 3w4
Jean Armstrong - ISFP, 9w8?
Furio Tigre - ESTP, 8w7
Victor Kudo - ESTJ, 1w2?
Viola Cadaverini - ISFJ?, 9w8
Godot - ExTP?, 6w5?
Terry Fawles - ESFJ?, 6w7
Sister Bikini - ESFJ, 2w3
Sister Iris - ISFJ, 9w1?
Elise Deauxnim - INFJ, 9w1?
Apollo Justice - INFP seems plausible, though I'm quite clueless about his enneatype
Trucy Wright - INFP?, 9w8?
Kristoph Gavin - IxTJ, 3w4
Klavier Gavin - ENFJ, 3w2
Wocky Kitaki - ESTP, 6w7 or 7w6
Plum Kitaki - xSFJ, 2w3
Guy Eldoon - ESTJ?, 6w5
Wesley Stickler - INTP?, 5(w4?)
Alita Tiala - ISFJ, 2w3?
Lamiroir - ISFP, 9w1?
Valant Gramarye - ISFP?, 3w2?
Daryan Crescend - ExTJ, 8w7
Vera Misham - INFP?, 5w4
Drew Misham - ISTJ?, 5w6
Spark Brushel - ENTP?, 7w6?
Jacques Portsman - ExTP, 3w2
Rhoda Teneiro - ISFJ, 6w7?
Cammy Meele - ISFP, 9w8
Zinc Lablanc - ESTJ, 6w5?
Shi-Long Lang - ESTJ (maybe ESFJ), 6w7 (very much counterphobic)
Kay Faraday - ENFP, 7w8?
Ernest Amano - ISFJ, 9w8?
Lance Amano - INFJ?, 6w5?
Lauren Paups - ISFJ, 6w7?
Tyrell Badd - ISTJ, 6w5
Calisto Yew - ISTP, 7w8?
Byrne Faraday - xNFJ?, 1w2 or 6w5
Colias Palaeno - xNFJ?, 9w1 or 3w2
Quercus Alba - xNTJ, 8w9
Feel free to ask any questions!