Posted by: @oldbob

When a cavalry unit converts to an attack directive, the designated brigade and all other brigades that can reach the target must move to contact. Do the other brigades in the formation make a full move provided they stay in cohesion, or do they simply move far enough to remain in cohesion?

I'm unsure what you're asking. There is no sub-division of Formations except for the Unit (represented generally a single stand), so I'm not sure what you are referencing when you say "brigade". Can you clarify?

If an eight-stand cavalry unit attacks a five-stand unit. Six of the cavalry stands move into contact with the target unit. Do the other two stands simply move to stay in cohesion, or do they have to move as far as they can and remain in cohesion per the attack directive that says units must use all of their move towards the objective?

Posted by: @oldbob

If an eight-stand cavalry unit attacks a five-stand unit. Six of the cavalry stands move into contact with the target unit. Do the other two stands simply move to stay in cohesion, or do they have to move as far as they can and remain in cohesion per the attack directive that says units must use all of their move towards the objective?

Gotcha!

To answer: Stands (Units) that begin within range and arc of the target may move to contact. Any stands (Units) that begin outside range and arc must remain Cohesive but can't contact the enemy.

For reference: There's an example regarding this on page 57 (Step #2: Conversions, Moves) and you'll find the applicable rule on page 68 (5.1.3.Cavalry Conversions) in the 3rd paragraph.

To clarify 2.3.2.Attack [A] Directive doesn't require all Units to move their maximum, only the Regulating Unit, all others must remain Cohesive. Also: The Cavalry Conversion's move ignores the Force's Objective (per 5.1.3).

That help?

Yes.