I don't see what character usage has to do with them returning or not for MK11.
Imo, it has more to do with how they are well received they are among the fans, and the only proper way to do that is with a poll.
Character usage is vague, because while people could be using them on popularity, people could also just be using them based on how easy they are to use.
The Top 8 characters really aren't that hard to master in 1 variation or another.
Tremor was the #1 requested DLC character, with Fujin behind that, and yet he's 28 on the character usage list because people used him for a bit and likely couldn't get good with him, so they dropped him.
As for Trilogy characters, the ones returning are likely the ones that have been in the most games.
That said, I personally think that Sonya, Johnny and Jax can sit out (not necessarily dead), for once.
Scorpion, Sub-Zero, Raiden, and Liu Kang will always be in MK games because people can't let go of them.
I could also see Mileena returning, even though she's dead.
Much like Liu Kang, Kung Lao and Kitana, people will cry and moan if Mileena's not in, and MKX has proven that canon goes out the window if the crybabies complain loud enough for their characters.
Mileena will also likely have a non-canon default living costume.
People will also moan if Reptile's not in, because "ninja." :roll:
Ermac could be gone, for all I care.
That dude has had 0 character development ever since UMK3.
He's always someone else's henchman, much like stale Baraka, and Kano.
They tried again with Kano in MKX, but he was just a henchman again.
As for the rest of the Trilogy characters, the ones that aren't playable in MKX (aka dead or missing) can be swapped out for some of the current ones in MKX.
Kabal, Smoke, Sindel, Nightwolf, Jade, and Baraka can replace either Jax, Johnny Cage, Sonya, Quan Chi, Ferra / Torr (sadly
), Kano or Tanya.