Just like in the question...is it possible? is it possible useing aprijuice?
No, because if you use aprijuice to max a stat, another stat will go down, so no. Legendaries have the highest stats so use them.
I think pokemonblack is right, but sunkern and arceus can have each stat maxed out, just not all at the same time.
Yes you can Max out on the Pokealthon Stats. but not 100% Complete and the thing is it won't stay Maxed out forever. You must find a Combination of Arpicorn to find the one that is Right for your Pokemon and do the Pokealthon as Quickly as you can,the effect of the Juice will give you the Upper hand but you are also Limited for 1-2 Days.
Ditto can also have stats to the max