Okay, that's a lot to answer, I'll stick with the Gen 4 stuff for now
Shadow Lugia, maybe as a one off gag but not as a recurring character
Lake Trio, I like the psychic empathy idea, that's going in
I hadn't planned to use the origin formes for GPD, Palkia is definitely going to be... spacy
Cresselia is already going be very lovey dovey, pretty much every Mon is a sex freak in this world, she will be getting into your dreams but so will someone else
Heatran being a Futa has already been suggested and it's already being planned
Regigigas is organic, unlike her creations
Manaphy... my plan for her is one I need to ask about to see if people like it, I can try your idea if mine's not well received
Darkrai, yep, she's all planned out
Shaymin was always going to be a shortstack, but I can make her bottom heavy too
Arceus is definitely going to be on the kinky side, but her dialogue will be different that what you had in mind
Your later Gen ideas, I'll note down and come back to them when I get there, some of I'll certainly make use of
side Mons, I can add those, the Humans will probably be one off scenes too
The extra fetishes, maybe, but not the different pregnancies... well, maybe not
Marriage... later... MUCH later
I have no plans for a Discord