Comparing the Fox R1 and the Buena Vista R2 with this site, the latter is said to have a stereo track for the Troma dub. Since Streamline did all their dubbings in mono due to poor M&E materials, I don't know how accurate the specs are for the JP R2. The poster could've confused "Stereo" with "Dual Mono", or mixed it up with the 2003 Disney dubbing (as that was 2.0 stereo in all the recent DVD releases).
Does anyone have that disc to check if the Troma/Streamline dubbing is indeed stereo? If its the case, than it may be an upmix from mono, or Disney could've grafted the dialogue portions from the Streamline dub onto a stereo M&E track (Unlike Toei, I'm sure Studio Ghilbi keeps all their M+E tracks in good shape, as the 2003 dubbing used it unless they changed the songs and effects).
(to elaborate on the term "M&E", it means "Music and Effects")