At the risk of beating a dead horse on the Tonight Show thing...I have to imagine part of the reason he didn't appear was that he would have wanted to appear with his touring band, ala the Mike Douglas and Dinah shows.  I don't recall ever seeing another band leader appear on Carson with their own big band.  Small ensembles, yes, like Mangione, but never a 13-20 piece big band.  Buddy always came on as a soloist.  Could Doc and the Tonight Show orchestra covered any and all of Maynard's charts?  Of course.  Wouldn't it have been cool to see Doc back in the section playing lead behind Maynard?!