so those unlucky enough to know me on AH.com has seen most of this.
But, it fits better here.
As far as I'm aware there's no "Official" Cadance-verse group, and I don't see any point in making a group, unless there are people interested, so...here it goes.

-Luna and Celestia both fell into a Nightmare Moon/Corona phase, but were able to snap out of it due to Discord's free reign, and Cadance gathering a group of ponies who could use the elements.
out of guilt, both have isolated themselves from the rest of ponykind, leaving the world in a eternal state of twilight.

-Cadance steps in, but at this point she is young, weak, and inexperienced.
She finally mastered the ability to raise the Sun and Moon, but doing so leaves her exhausted, and makes it difficult to run a nation.
enter several ponies she trust to help her. These ponies are mix of her Element wielders, and those who supported and trusted her.
thousands of years later, this has evolved into a Council of a sort.
Cadance monitors these ponies, just in case their hearts are no longer in the right place. After all if all a pony cares about is getting an element wielder under his control, gathering all the most valuable items for herself, or is a Unicorn supremacist, that's not in Equestria's best interest is it?

-Among those who Helped Cadance include Blueblood's Ancestor, Rainbow Dash's ancestor, and The Doctor/Time Turner's ancestor. None of their ancestors were previous Element wielders. infact, we probably won't ever meet the descendants of the original Element wielders.

-there is no real Counterpart to being "Celestia/Luna's student". the sons and daughters of the council members are expected to take over their parent's spot once they have enough experience.
This actually varies from member to member, and in some cases their nephews/nieces/grandchildren/others have taken the spot on the council.

Some of the Families have Changed.
the Apples were once on it, but Granny Smith, who was on the council at the time, decided to retire the entire clan from their position.
while they are officially not part of the council, Cadance and the other council members do take their advice, and the overly ambitious Oranges, a cousin of the Apples, are trying to get into the council.

Thus, we bring in the main character, and one of the Elements;
Time Turner.

I have two potential origin stories for why he's being sent to Ponyville

Scenario 1: His ancestor is known as "The Doctor". His father is "Doctor VIII", and he has two brothers, an older one influenced by the Ninth Doctor, and a younger one (the Pegasus variant seen in "Sonic Rainboom") who's influenced by the Eleventh Doctor. Because it was always expected that Doctor IX was to take their father's place as the next council member, Time Turner become a somewhat awkward, rambling oddball, with a bit of technomastery
essentially the Tenth Doctor.

When Doctor IX decided he would rather join the military, Time Turner got shoved into the spotlight. While well educated, his social interactions are...less than stellar.

His Father and Princess Cadance, decide to send him to Ponyville, along with Blueblood and maybe Rainbow Dash, so that he can become a better pony.

Scenario 2: No siblings. His ancestor is "Time Turner I", making him "Time Turner X" (or XI if he's more based on the Eleventh Doctor, rather than the Tenth).
other than that, it's similar to scenario 1; sent to ponyville to become a more well-rounded pony.

Either way, he's the Element of Magic.
Why Magic?
because Friendship is Magic.

More seriously, it's because I think people take the name of the element way to litteraly. Twilight's some super-special once in a lifetime prodigy, while Trixie is more stage magic and sleight of hoof.

Magic isn't just that. Part of the Element of Magic is watching his relationship with the other elements, as well as other ponies, grow and become stronger.
It's how he become a suitable successor to his father on the Council, and how he helps his friends.

will post more thoughts it people are interested.

I thought the process of creating a 'verse was either collab projects with multiple authors each writing one character doing things simultaneously with the other characters in the project, or something along the lines of "You guys want to write fanfiction of my fanfiction? You have my permission, go ahead."

This doesn't seem to be a collab project, so you'd need to write the first story in this before it could come anywhere near being a 'verse.

As it stands, you claim this is the "Cadence-verse" but your outline merely mentions a bit of backstory regarding this and then jumps off to become a Doctor Who crossover, so I'm a bit skeptical that you could make this work.

480351

This is simply some stray thoughts I had.
Nothing is really fleshed out, and to be honest, I want to get ideas and thoughts from other people. What others can come up with can be better than what I have, and might make for a better story.

I'd rather have afew people come together, throw some ideas around for the backstory, who can be what, and so on, and then throw together a story that can lead to more people getting interested and so on and so forth.
Then it feels less like one person dictating the general overview, and more like people working together to make something they all agree on.

hence the use of the word "Idea". It's still brainstorming, and I want to offer people a chance to make it something they would like to see.

As for "Doctor Who Crossover", I don't understand how you got that idea.
there's not going to be a ponyfied version of Daleks, the Master, or what have you.

Outside his ancestor's name and a few quirks meant as a wink and a nod towards what the fandom chose to make him, he's his own pony.