Like Classic Grigri and Classic Zina's motive, his plan is to raid any places on finding any candy that he and the Mascrapules can eat. However, the classic counterparts of Les Pyjamasques are always here to thwart their plans from getting away with it.
Classic Ulbert's powers are identical to Ulbert, so there's no difference to his powers.
He appears less bratty and spoiled than his modern counterpart, but he still retains his mischief mindset towards the Pyjamasques.
Classic Ulbert is identical to Ulbert, so nothing was different to his appearance.