Is there any difference between the 3 versions?
Not enough to really matter much.
There are three models of Pal Mickey (and they ALL still work in all WDW theme parks).
V1 - Pal Mickey "Classic" (that's what I call MINE). V1 comes dressed in the classic Mickey of red shorts outfit.
V2 - Pal Mickey "50th Anniversay Special Edition" (HCoE). V2 comes dressed in a black TUXEDO.
V3 - Pal Mickey "Year of Million Dreams." (Current Model) V2 comes dressed in the Sorcerer's Apprentice Robe and pointed hat. (He ALSO has on a shorts outfit on under the robe.)
You can find Pal Mickey's on eBay. You can tell which model he is by the outfit.
The V1 Pals where $50 when new.
V2 and V3 Pals were $65 when new at WDW.
There is not really a LOT of difference between them, except:
V2 and V3 PM "speak" a bit louder than V1.
V2 and V3 PM can describe the few newer attractions that weren't open when the "classic" PM was first introduced. (Not a big deal.)
V2 and V3 PM has a slightly larger "library" of things he can say (and sing!)