The AI is set up to wait a round before equipping weapons to prevent it breaking. If you want someone unarmed to equip a weapon then you need to do that before turning them hostile and initiating combat. Try something like this:
#include "k_inc_generic"
void GoHostile() {
ChangeToStandardFaction(OBJECT_SELF, STANDARD_FACTION_HOSTILE_1);
DelayCommand(1.0, GN_DetermineCombatRound());
}
void main() {
object oDarkJedi02 = GetObjectByTag("tat17_darkjedi02", 0);
object oDarkJedi03 = GetObjectByTag("tat17_darkjedi03", 0);
ActionEquipItem(GetItemPossessedBy(OBJECT_SELF, "ITEM_TAG_HERE"), INVENTORY_SLOT_RIGHTWEAPON, FALSE);
AssignCommand(oDarkJedi02, ActionEquipItem(GetItemPossessedBy(oDarkJedi02, "ITEM_TAG_HERE"), INVENTORY_SLOT_RIGHTWEAPON, FALSE));
AssignCommand(oDarkJedi03, ActionEquipItem(GetItemPossessedBy(oDarkJedi03, "ITEM_TAG_HERE"), INVENTORY_SLOT_RIGHTWEAPON, FALSE));
ActionDoCommand(GoHostile());
AssignCommand(oDarkJedi02, ActionDoCommand(GoHostile()));
AssignCommand(oDarkJedi03, ActionDoCommand(GoHostile()));
}