Fer I'm thinking of Dark Empire I & II which were written as sequels to the Thrawn Trilogy and had some elements incorporated into the Jedi Academy trilogy. All in a relatively short amount of time.
was not written as a sequel to the Thrawn trilogy. Work began on it when Marvel still held the license in the late-80s. (It was going to be published through Marvel's Epic imprint.) Lucasfilm Licensing made Dark Empire
fit after the Thrawn trilogy (because Zahn didn't want to have to incorporate it into his storyline), but it was always an independent project from Zahn's work. The Jedi Academy
trilogy was then made consistent with Dark Empire
because KJA said that a wrecked Coruscant really made no difference to his story. (I believe he was given the option of rejiggering the story to go before Dark Empire