An odd example, but many of young!Edgeworth and young!Franziska's interactions in Turnabout Reminiscence. Many of them verge on Crowning Moment of Funny, but it's also sweet to see how these two overly serious, strictly-raised geniuses can act like childish siblings. It's also apparent how they do care for each other, even if they have trouble showing it. Some scenes of note are Edgeworth saying that maybe one day they can fight crime together as two equal prosecutors, and when Edgeworth briefly wishes he had the power to give the decorated knife to Franziska as a gift, since she seemed almost entranced by its detailed carvings.
In the first Investigations game, during the flashback to Edgeworth's first properly meeting Kay, the dialogue gets increasingly focused on the Promise Book that Kay and her father made and how much Mr. Faraday cared for Kay. It's made increasingly heartwarming because Gumshoe nearly got himself arrested on a double murder charge to cover up Kay breaking one of her promises.
Being an odd mix of this, a Tear Jerker and a Crowning Moment of Funny, during the flashback case we get treated to this: When talking to Kay, you realise that she kept a Swiss Roll that she'd bought on her "for her daddy". This is the Tear Jerker part, as we all know that her father is dead. And so does she. The Crowning Moment of Heartwarming was when Edgeworth, drawing comparisons between her father's death and that of his own father (having both been killed when they were about 9 or 10, in a courthouse), decides to have a Pet the Dog moment and, getting down on one knee, offers her a handkerchief and encourages her to let it all out. She starts to cry, and she runs towards him, presumably to get a hug...only for it to become a Crowning Moment of Funny when instead of using the handkerchief, she instead blows her nose on his cravat. His expression is priceless. Still, the moment is incredibly heartwarming when you think that this happened years before his Heel-Face Turn.
When both Miles and Franziska commend Kay for her bravery following her father's death.
Kay: Even if I can't see Daddy any more, I'm still going to keep all my promises.
Edgeworth: You're a very brave girl, Kay.
Franziska: You're a very good child for keeping the promises you made to your papa. I'll even testify that you didn't cry, just for you.
After getting Kay off the hook for the murder of Manny, Miles reprimands her for being reckless. Kay looks down at her shoes and apologises, saying she'll be more careful, only for Miles to tell her, "good girl. It's good to conduct some self-reflection every once in a while." Kay, at this point, tells Miles that he reminds her of her father. Awwwwww <3
"Don't worry, Maggey! I'll always be there for you!" D'awwwwwwww, Gumshoe, you sweety!
How about when we see Kay defend Gummy by kicking Miles? and she attempts to do it again later? This troper find it quite heartwarming to see Kay defend Gummy, her new friend by bonding over with a Swiss Roll. And let's not forget Gummy sticking up for her by not revealing her presence in the beginning. That's friendship at best.
Lang:I think I'll give trusting you a try, Mr. Prosecutor... or rather, Mr. Edgeworth.
Lang:I leave this critical battle up to you, Mr. Edgeworth!
Tateyuki in Investigations 2 still firmly believes Edgeworth and Manfred von Karma are Not So Different. Then Gumshoe and Kay get sick of it, giving him a massive speech on Edgeworth's Character Development and how he's no longer an Amoral Attorney. Even Edgeworth opens up a fair bit more than he has in the series. (Tateyuki even lampshades it.)
The ending of Investigations 2 Case 4 where Kay regains her memories and she gains them back when Edgeworth gives her the promise notebook.
In that case, it was more like... "I am Kay Faraday...The Great Thief Yatagarasu!" *The Great Truth Burglar starts up* D'awwwwwww.
Whether you like her or not, you have to admit it was sweet of Edgeworth to thank and give a bow to Oldbag after the Samurai Dog turns out to be a crucial piece of evidence.
Surprisingly enough, one of the possible dialogues for presenting wrong evidence to the Big Bad in the second game contains one of these. Tateyuki tells Edgeworth he believes in him and encourages him not to give up. It's actually very empowering for the player given what usually happens in wrong evidence dialogues.
A very surprising one happens during the ending. Gumshoefinally gets his salary raised for once!
In both games, whenever Phoenix is referenced it's usually Edgeworth reflecting on or referring to ways in which Phoenix has changed him.
"('Contradiction?' He must be rubbing off on me.)"
"(What would he do in a situation like this...?)"
"Perhaps a younger version of myself wouldn't have been so reckless. ...I had been given some power, so I thought myself justice. Just as you are now... However, a certain man was able to strike down my selfish sense of justice. Ever since then, I have viewed others differently. I am even able to serve as a prosecutor only because of the support of those around me. Those like Detective Gumshoe, and all the other investigators.. and Kay too, of course. To be honest, I too was surprised by how much I changed..."
Later he refers to Phoenix less obliquely as "A certain friend". Phoenix might not appear in these games, but let it not be said he doesn't have a presence of a different kind.
At the end of Investigations 2 Ryōken saves Sōta, asking for his life to be spared out of love for him. Ryōken then returns to prison with Sōta, but assures Sōta that they are simply going home.
There's a parent-and-child theme running through Investigations 2, showing many varieties of these relationships, from unhealthy to very healthy to families of choice. Seeing this theme culminate in Edgeworth taking on a borderline Papa Wolf role with Kay in case 4, a nearly fatherly tone in his support of Yumihiko when he calms him down and pulls him out of the Despair Event Horizon in case 5, and the way he actually communicates fine with Shimon despite claiming to be no good with kids is very rewarding and might cause the shed of Manly Tears. His father would be proud of him.
Quite a lot of the last scenes in the game are heartwarming, but this exchange really stands out.
Edgeworth: The only way to right these contradictions of the law is by joining the court system. The one who could save Sota Satashiro was not an attorney, but rather a watchman of the law: a prosecutor. I shall face the contradictions of the law as a prosecutor.
Shigaraki: .......... I get it. That's just like you. But you know... it won't be easy. You're not aiming for the ordinary. Instead, you're planning to fight the law itself.
Edgeworth: I know. However, someone must.
Shigaraki: Yeah, yeah. I believe in you, too. Both the law and people can grow, you know. I'm sure you can pull it off. After all, you're Gregory's son. Gregory would never give up, no matter what. His eyes always saw only what lied straight ahead. Miles... Your eyes when you chose to live as a prosecutor looked just like your father's. It looks like you've grown a little. I really want Gregory to see this.
Any of the odd moments where Edgeworth actually acknowledges that Larry is, in fact, his friend. Heartwarming, because he seems even more annoyed with Larry than anyone else, but like Phoenix, seems to look after him as if he were Larry's older brother.