So I saw the Wabbit episode "Raising Your Spirits," which had a thunderstorm in it (to add to the ghost mood), and despite the show using tons of Hanna-Barbera sound effects, they didn't use "Castle Thunder" at all. I mean, come on, you're gonna use all of those H-B SFX, which are out of place with the Looney Tunes, but not the thunder sounds H-B used?! It's just like the 1967 Looney Tunes cartoon "Fiesta Fiasco" (again, many H-B SFX, but just the old Warner Bros. thunder sounds were used) and "What's New Scooby-Doo" (they did use Castle Thunder at the beginning of one episode, but then just stuck with new custom-recorded (and LOUD) thunder sounds for the rest of the episode.)
If only the sound editing for the show was done by DigiPost.TV or someone other than Advantage Audio, then we wouldn't have this...
Oh yeah, it's also worth noting we now have two versions of the "Wabbit" theme song. There's the initial one, which is very similar to Disney's "TaleSpin" theme in style, and then we have this "wackier" bluegrass version.