When it comes to choosing your witnesses and minor characters, there are two ways to go about it -- using canon characters, and using original ones. If you're using canon characters, keep in mind that not only will you have to study their character a little bit so you can write for them properly, but also that you need to come up with a logical explanation for why they're involved. There are some characters, like Maggey Byrde, who could reasonably be anywhere at any time. On the other hand, if you make Morgan Fey the head chef at Tres Bien, people are not going to take you seriously.

When it comes to original characters, you have more freedom with how you can use them. If you can come up with (good!) custom sprites, you can just go crazy wherever and nobody will care. But unlike with lawyers, it's completely forgivable to use pre-existing sprites for these characters as well. Here you run into a problem, though. The temptation will be to pick the character that best reflects your OCs personality; if you do this, however, people may feel your character is too much like the existing one, which can completely ruin their chances of being likeable. If you're lucky, you'll be able to find a sprite that fits the role appearance-wise and still has great animations for your character, but all in all it's a tricky prospect. If you can't find one that works without being too similar, I highly recommend going to the Your Art board and asking somebody there for help with custom sprites.

Some Ace Attorney sprites I would never use for original characters due to their personalities/ridiculousness: April May, Diego Armando, Mia Fey, Ema Skye, Mike Meekins, Jake Marshall, Damon Gant (a very popular pick that I disagree with,) anybody from Turnabout Big Top, Matt Engarde, Shelly de Killer, Dahlia, Luke Atmey, Ron DeLite, Jean Armstrong, Lisa Basil, Bikini, Iris, Elise Deauxnim, Olga Orly (only the first outfit,) Wesley Stickler, Lamiroir/Thalassa, Machi, Daryan Crescend, Valant Gramarye, Zak Gramarye.

Some good choices: Any character that is unimportant or dies early on is a great choice. I'd recommend Redd White (rich man,) Will Powers (normal man, tough guy,) Penny Nichols (teenage girl,) Cody Hackins (young boy,) Sal Manella (nerd,) Yanni Yogi (old man,) Angel (pretty/seductive woman,) Turner Grey (paranoid/angry man,) Adrain Andrews (typical woman,) Desiree DeLite (same,) Viola Cadaverini (sickly/injured woman,) Hobo Phoenix (surprisingly, he's an effective normal man,) Alita Tiala (younger woman,) Romein LeTouse (government/businessman,) and Vera Misham (shy girl.)

Since Bitter doesn't work for this, I'm going to use an example from An Angry Canuck's trial Turnabout Escort.

Character selection: Apollo is a great choice for defense because the case is right up his alley -- full of unusual and exasperating witnesses. There's both a good and a bad example of OC sprite selection: for Asterik DuGaulle, An Angry Canuck chose Damon Gant, but the two are a little too similar and it can feel awkward at times. On the other hand, we have Turner Grey's sprites representing Whit Ness. Turner isn't in the main series long enough for his personality to be fully fleshed out, whereas Whit Ness is a very different character who easily becomes a memorable part of the trial.