Are the majority of characters in Formic Wars new?

Question

Although Mazor Rackham is one of the central heroes of the Formic Wars: Burning Earth and Formic Wars: Silent Strike series, there are other heroes that play a much more significant role in fighting the Formics, such as Lem Jukes, Victor Delgado, and Imala.

Were any of these characters mentioned in any of the Ender books (or other earlier Ender stories, like those in Intergalactic Medicine Show), even in passing?

It seems odd (in-universe) that they aren't well known, even though Mazor has a larger role coming in the Second Invasion (supposedly including realising that the Formics have a central intelligence, although Imala and Lem figure that out in issue #4 of Silent Strike).

Answer 1

Lem Jukes definitely isn't listed anywhere in Enderverse books. I re-read all of them recently, and just now did a search.

His Graphicly page states:

First Appeared In: Formic Wars #1
Created By: Aaron Johnston

Ditto Imala. Plus, her Graphicly page states:

First Appeared In: Formic Wars #1
Created By: Aaron Johnston

I don't recall any mention of Victor Delgado in the books either, but he doesn't have a Graphicly page to collaborate that.

For contrast, Mazer Rakham's page states:

First Appeared In: Ender's Game
Created By: Orson Scott Card

Answer 2

As of now, all of the characters (other than Mazer Rackham) from the Formic Wars books are new characters. However there are characters related to previously mentioned characters.

In The Swarm (Formic Wars #5, Second Formic War #2), we meet a character named Prem Chamrajnagar.

Mazer exited the lunar shuttle via the docking tube and found a young female lieutenant waiting for him at the gate. She came to attention and saluted. “Captain Rackham. I’m Lieutenant Prem Chamrajnagar. I’m your appointed attorney for your court-martial.”

Prem Chamrajnagar is related to Admiral Chamrajnagar from Ender's Game, who becomes Polemarch in Shadow of the Hegemon.

This is hinted at in The Swarm with a line about Prem having family in the Fleet.

For the moment,” said Mazer. “But I’m hoping you’ll have dinner with me and Kim again once this is all over.”
“Only if we have some of that stir-fry again. And hey, keep your eye open for my family. I have a lot of brothers and uncles in the IF.”

Aaron Johnston, the author of the book has clarified that this was intentional.

AJ: There's another character in The Swarm that's related to someone else in Ender's Game. Mazer's attorney.
Q: You must be referring to Prem Chamrajnagar...I saw that she mentioned other "brothers and uncles" in the Fleet, and those must be the close relatives of the future Polemarch.
AJ: Yes. Prem. Mazer will remember that name.