Questions arose

Does a pivot count towards movement for an artillery piece with RELOAD?

Does a Wizard have to see an entire unit to cast a fireball against it?

Ty in advance, S

Yes. It’s not a “halt” action.

from rulebook page 38:
Reload: The unit can only make ranged attacks if it received a Halt order in its previous Movement phase.

No, see shooting rules. If the wizard can draw line of a sight to only a tiny bit of the unit, it can cast a fireball. Note that in such a case, the unit has cover.

Edit: from the rulebook page 26:

PICKING A TARGET: A unit can pick a single Enemy unit as a target for its ranged attacks as long as all the following conditions are met:
•The target is at least partially in the unit’s front arc.
•The unit has LoS to the target.
•The distance between the unit’s Leader Point and its target is equal to or less than the weapon’s or spell’s range.

And from page 15 concerning line of sight.
Certain actions, such as charging or shooting at an enemy unit, will require you to determine if your unit can see another unit. This requires drawing an imaginary straight line, called the Line of Sight (LoS), from your unit’s Leader Point to any point on the target’s base.