So there was this one promo of Ed, Edd n Eddy that had what seemed to be an extended version of the theme song with some trumpet improvisation at some point:
Getting in contact with the series composer through his website's contact form, I actually successfully got a response back from him with the following:
Now, if he wasn't mistaken, this would mean the specials' music would of been prepared for at the same time as this promo was made or something. Checking the specials themselves, I don't think the halloween/xmas/valentines specials at least in their credits had this trumpet composition in them. I sent him another email with this info in it.