Original Post
Double-post again, sorry! I mean, I should’ve gone to bed two hours ago so I really shouldn’t be writing this anyways, but quick update so I don’t forget in the morning.
Episode 5’s CGs are all implemented and functioning to the best of my ability, as well as some minor script changes in Ep5 (typo/line break fixes, starting to standardize Dlanor’s capitalization, things like that). I think the scenes still work as they originally did with the original PC sprites enabled, but I’ve still got to test things out properly. Also, I have no idea if he’s got an account here, but I’d like to give a shout-out to drojf on the 07th Modding Discord for helping me step through part of the code to figure out why one of my CG insertion attempts was failing (thanks to their help I also managed to nearly seamlessly “fix” Erika’s introduction bugging out when toggling sprites).
I’m also starting to look into making a voice-compatible version of this mod - anything concrete is probably going to wait until the rest of the CGs are implemented, so I don’t have to manage two different files side-by-side, but it should be relatively simple.
Once I wake up, I’m planning on doing another quick runthrough to see if things function as intended, then I’ll upload an “alpha” version somewhere and update this post. Just in time to fully reread Ep5 for the podcast, huh? 
EDIT: An initial release of CG restorations for Ep5 is here! Download the archive, and extract the file and folder within to your Umineko Chiru directory (where Umineko5to8.exe and 0.utf are located). I highly recommend backing up the original 0.utf file first. This isn’t yet voice-compatible, so it can’t be used alongside the voice restoration mod just yet, unfortunately.
Also, as a warning: There is a good chance that save files made on the original or voice patched version of the game will break if loaded. Things like character sprites not getting cleared properly, CGs not loading, getting moved backwards a few lines, possibly even crashes. Bear that in mind before reporting any bugs.
I’ve tested this, and it should work as intended. There may still be some bugs or odd behaviour when switching between old and new sprites, but just about everything should function the same as before with old sprites on.
I’ve also made a few changes to the script here and there - minor things like standardizing Dlanor’s dialogue capitalization, including punctuation marks in coloured text, and so on. Going to edit a (overly) detailed changelog into this post shortly.
If you do encounter any bugs, a screenshot and description would be helpful in figuring out how to fix them. I’m also open to feedback on whether or not any of the CG appearances should be moved or removed, as there’s nothing in the script natively to indicate where they were intended to go.
I hope you enjoy it! 
EDIT: Changelog
- Total of 31 new image definitions have been added - 30 are CGs (7 per episode plus two labelled “end” - note that none of them besides Ep5’s are used as of yet), one is a background
- Additional subroutine added to display CGs during certain sequences - currently only used once
- Episode 5 prologue - 1 CG added (Lambda: “I’ll be the next Game Master. Any objections?”)
- Episode 5, “Furudo Erika” - 1 CG added (Erika: “I am called Furudo Erika. My deepest apologies for disturbing you members of the Ushiromiya family like this.”) (fun fact: this is where that background mentioned earlier is used, to circumvent Erika’s sprite disappearing if graphics are toggled between old and new sprites)
- Episode 5, “Morning of Tragedy” - 1 CG added (“Natsuhi flew into the cousin room on the second floor of the guesthouse…”)
- Episode 5, “Ten Wedges to Pierce Witches” - 2 CGs added (“The air shone brightly, and the piece Erika had guided there showed its form…”, “[Beato] drifted down through the rain treasure box world into Battler’s chest.”)
- Episode 5, “The Great Court of Illusions” - 1 CG added, used three times (Dlanor: “Permission to unsheathe the ‘Red Key’.” for first instance)
- Episode 5, ??? - 3 CGs added, used six times - one reused from Ten Wedges to Pierce Witches, one reused from The Great Court of Illusions (“Slowly, …Dlanor stepped forwards.” for first instance)
- “Know that you cannot leave through the door without Natsuhi thinking something was odd.” - Period is now red
- “Let it be said that Natsuhi did not hear the sound of the door opening while in the room.” - Period is now red
- “Was it shown beforehand that a blind spot existed within the study for Natsuhi? If it wasn’t shown, this theory will not be permitted.” - Permitted is now capitalized
- “Knox’s 9th. It is permitted for observers to let their own conclusions and explanations be heard!” - Heard is now capitalized
- “Please, allow me to speak. All victims’ deaths were homicides.” - Changed to “All the victims’ deaths”
- “Know that no examination of the corpses could have been mistaken!” - Exclamation mark is now red
- “Know that no corpses exist except those of characters who have appeared in the story.” - Period is now red
- “Know that the red truth is simply truth, and there is no need to provide evidence or proof!!” - Exclamation marks are now red
- “Knox’s 2nd. It is forbidden for supernatural agencies to be employed as a detective technique.” - Technique is now capitalized
- “…In this court, if anyone other than witches is going to speak the red truth, they’ll have to construct an appropriate proof for it.” - Changed to “if anyone other than a witch”
- “…the tale will continue on, …Battleeer…” - Removed one e in “Battleeer” to prevent poorly placed line break (not fully satisfied with this, will look into again later)
- “The red truth from the previous games says that Kinzo is already dead.” - Period is now red
- "“He isn’t on the third floor or the first floor or the basement…” - Stray quote mark at beginning removed
- “I wanted to believe that […] Natsuhi just might have been able to grasp a sliver of happiness…” - Changed to “Aunt Natsuhi”
- “…The witch with the hopeless gaze…” - Extra space added at start to prevent poorly placed line break
- “…Thank you… …Liar… …Goodbye… And… …Sorry.” - Attempted to center text on-screen - not happy with this, but I don’t think I can center it any better than this, might scrap it
- “In that case, Battler, …let us say that the 3rd Commandment didn’t exist. In that case, what would happen to closed room mysteries…?” - Exist and mysteries are now capitalized
- “Isn’t that convenient? What clever little words to hide your own incompetence.’” - Stray apostrophe removed, line is now in quote marks to indicate dialogue
- “…In other words, there is a chance that you could win.” - Win is now capitalized
- “The writer who wouldn’t write until he gained the support of readers…goes for all eternity without releasing his maiden work.” - Space added between readers and ellipses to prevent oddly placed line break
- “The reader who waited for the writer’s rise to fame…goes their whole life without knowing the joy of the mystery genre.” - Space added between fame and ellipses to prevent oddly placed line break
- “…when does this ‘the chicken or the egg’ type of shy love reach the level where can it progress into mutual love…?” -
Changed to “where it can progress” - “Why did you lose heart…before me?” - Space added in middle of ellipses to prevent poorly placed line break
- “…Why couldn’t…you say it…more simply…?..Idiooooooooooooot!!” - Space added after question mark to prevent poorly placed line break
- “Lady Erika’s reasoning has solved the 5th GAME. No new facts exist that overturn the truth created by this reasoning…!!” - Reasoning is now capitalized
- “Knox’s 1st. It is forbidden for the culprit to be anyone not mentioned in the early part of the story!” - Story is now capitalized
- “Knox’s 8th. It is forbidden for the case to be resolved with clues that are not presented! Was there ever any foreshadowing showing that you might be the baby from 19 years ago?!!” - Presented and ago are now capitalized
- “Knox’s 2nd!! It is forbidden for supernatural agencies to be employed as a detective technique! If you would show that Kinzo has died with the red truth, then I demand that you display proof of a Human’s truth that could be used to make that point…!” - Technique and point are now capitalized
- “In this case alone, and with the red truth specifically, no counterargument will be valid…!!” - Valid is now capitalized
- “And that itself suggests the possibility that this corpse is a body double! This unidentifiable corpse cannot serve as proof of Kinzo’s death…!!” - Double and death are now capitalized
- “…It cannot be used as foreshadowing to form a basis for Knox’s 9th…!! Mistaking one thing for another is a right permitted to all observers!!” - Observers is now capitalized
- “All of Aunt Natsuhi’s schemes to make it seem Grandfather existed were hidden in the relatives’ blind spots…” - Changed to “to make it seem like Grandfather existed”
- “…In other words, this proves that the observer was not OBJECTIVE… Is what you are SAYING…?” - Changed to “Is that what you are SAYING…?” - might revert since this wording is used elsewhere, it just stuck out to me here
…Now that I look at it, that’s a lot more changes than I thought it was. Whoops. 