Dimitri would go from "KILL THEM ALL !" to "try and SAVE THEM ALL !" in Part 2. In fact a neutral/ GD ! Dimitri would've had some solid poetinal for that golden ! route some are after. But in true 3H's style, in dies in the end trying to save all the students and maybe the other two Lords ? And Byleth takes over. Or maybe even King ! Dedue. But got to have that "avatar worship", I suppose.
Claude would become that sinister sneaky boy, that some are disappointed that he didn't become. Cruel, manipulative, everybody would become his puppet, especially Byleth. Though again, in true 3H's style, despite all this sociopathic behaviour the world is now free from the church's merciless ways and peace is won. I think to make Claude more likeable here ( just imo), the church would have to be even more malevolent than it is in canon and Rhea would have to be less grey and the true villian of the story instead of the "Mole Men", hiding away.
Puppet Master ! Claude would also have such a "good time", with GD ! Dimitri, and would just become his playdoh, so easy to mold. Same with BL ! Edelgard. I think if you played this route, after defeating both Dimitri and Edelgard in battle, they would be so messed up and confused, they would perform the final blow themselves.
But no more, truly evil Church, so it's all good.......right ?!!!
Mole Men ? Oh, Claude knows. And he's using them like chess pieces, of course.
Claude would easily become my favourite Lord, to my least favourite FE lord.......ever. A nasty piece of work, that does a good thing. In short.
Edelgard despite going through a horrid and dramatic past still seems to at least have a strong head on her shoulders, so no Feral ! Edelgard here. Maybe. However, she'll still want answers and she'll still want revenge for what happened to her Kingdom. Edel's Flame Emperor disguise could maybe used here as a shield, as there's maybe still assassin's about, so somewhat traumatized and on edge, she takes up the role as Flame Emperor to gather and collect info, and hopefully one day strike down whoever was responsible. However, again, in 3H's style, turns out her trusted Uncle was responsible, and she has to deal with that fact and kill her Uncle who she thought was her only true and real friend in this world. Edelgard almost snaps, and almost becomes Boar ! Edelgard, but she's stopped by Byleth, who she also begins to struggle to trust. In the end Edel has succeeded in her revenge and is now Queen of a peaceful land from Emperor Claude's war, however unless you S-rank her with Byleth, it's said that not long after her victory, Edel did lose her mind a bit, and attempted to murder Byleth and gave up her throne to somebody else. Also, Edelgard has no clue about the "Mole Men", this time around, and had no clue that her Uncle actually died during the massacre, and had his body taken over.
Just like Dimitri, her story becomes a tragic one.
If you play GD ! Dimitri's route, I think you could be able to "save" Edelgard here, somewhat. Edelgard would have her showdown with Uncle mission, and Dimitri would whack out Emp ! Claude and Mole Men. No more Dubstep parties for you Mole Men, it's been canceled.
Rhea: Rhea would become the villian route, to give Emperor ! Claude more greyness towards his character. Sliver Snow, instead of being the somewhat neutral route, would become the Bad Guy ! route. Rhea would be in one in charge of the crest experiments and would absolutely execute anybody that steps out of line, and that line is thin. Rhea truly rules the world in fear and horror. I think Seteth and Flayn, would stay the same, but they would be doing what they do, out of fear of Rhea than the Slithers. In this route, you stop Claude, you stop Edelgard from discovering out too much info, and you stop Dimitri from attempting to stop you. After the war, Rhea is able to rule for many more years and people are miserable, but are masking it well. Seteth and Flayn also ask you why you sided with Rhea and why you didn't stop her. This is when Rhea taps Byleth on the shoulders, and gives Byleth the Church and full power, mentioning that she/he's not the failure that she originally thought.
Just like Claude, she's using the Slithers, to make them out to be these "evil, horrid, underground people ", when in reality, they are just puppets of Rhea and Claude. Rhea is using them out of fear, and Claude "promises to help them from Rhea", which are lies.