How much work and time would it take to add additional characters? Maybe someone like Genfu? Sweet Revenge said he'd consider coming back if he was added so I'd like to see that happen. If you've covered this in chat for a stream, I apologize.
so there's three-ish ways to "add" characters depending on what you're trying to do and how faithful you want it to be:
One is kinda boring, but you can cheat engine your way into boss raidou, prototype raidou, or some phase 4 copy that has the broken tenfu p+k and didn't get some other patches. I could add a code section to apply the various changes to boss raidou and make blackout stance work differently so it wouldn't be annoying, etc... BUT you'd still have to CE into the character which makes it non-viable in my opinion.
second way is i could take, say, eliot and rework his animations and move properties into playing like gen fu, and on the client-side you could model/voice/etc swap eliot with gen fu if there was a model formatted correctly for doa 6 (this is possible to do, I haven't done it myself but it's just the same as costume importing you see around) but you couldn't play eliot vs gen fu like this and the throws mostly wouldn't be correct, and this would be worse for any case where the animations aren't available but i could probably turn lei fang into a badly animated pai if your standards for that are very low. This also seems unacceptable to me, maybe it's viable as a side-event at an offline where somebody has a totally jacked up version of the game that plays like more VF and has VF models and an interpretation of their frame data. if you want to "add" a character properly with this method you might use the phase 4 or one of the raidous and then CE to access the character, who would look and sound like those story mode enemies without further client-side modding.
third is the thing you're probably thinking of where there's space in the UI for three more portraits and we'd have to edit a bunch of stuff I'm not sure anyone has ever touched to add content to the UI. I don't have the technical qualifications for this one but there's presumably some tables we'd need to add entries to for how the game draws the UI elements and knows how to find the character data etc, which is maybe possible but alex and I can't add animations yet (working on it, kindof) or change free-step speed so we'd need to figure out pretty much all of that stuff on top of making the character selectable via cheat engine and then eventually via the UI... and then we need to figure out if that would work online at all since it's modifying more than character data... and then we'd need to figure out how to make the installation process simple enough for those of us who didn't have the privilege having a PC at home as a 4 year old.
so... very hard, unless you really specifically want a slightly shoddy copy of gen fu and don't care if we delete eliot. And even then it would be a lot of work on my end when i could be doing something else like dialing in the colliders. Adding leon etc we'd need to import animations and i don't even know what would go into making his throw see walls the way it used to, even after we have all the other things.
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IF YOU WANT TO HELP WITH THIS STUFF IN PARTICULAR:
1. figure out how to change the UI things to make boss raidou, prototype raidou, and idk, "clone 5" accessible from the character select screen (and random filter screen)
2. figure out what the .g1a files are doing so we can create and/or modify them in a usable way.
2a. especially figure out how to get a .g1a from the old .mot files that the other doa games use
3, solve the face rigging problems that the model import guys have because of how jacked up the face rigging is in doa 6
4. help the other koei tecmo modders figure out what's going on with their stuff, decrypt strangers of paradise file names etc and maybe we can use those animations if they're rigged for humans, or they can put animation-correct hayabusa in their game, somebody in one of those communities might work out the file structure etc.