Okay, das ist dann leichter machbar.

Im Scriptslot Scene_Battle1 wird ziemlich am Anfag der Methode main das Fenster erstellt.
Code: 
s1 = $data_system.words.attack
s2 = $data_system.words.skill
s3 = $data_system.words.guard
s4 = $data_system.words.item
@actor_command_window = Window_Command.new(160, [s1, s2, s3, s4])
@actor_command_window.y = 160
@actor_command_window.back_opacity = 160
@actor_command_window.active = false
@actor_command_window.visible = false
Hier müsstest du die entsprechenden Elemente für "Attack" und "Defend" entfernen => @actor_command_window = Window_Command.new(160, [s2, s4])

Dann geht es weiter mit den Aktionen, die für die entsprechenden Befehle ausgeführt werden. Das passiert in der Methode update_phase3_basic_command in Scene_Battle3
Code: 
# Branch by actor command window cursor position
case @actor_command_window.index
when 0  # attack
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 0
  @active_battler.current_action.basic = 0
  # Start enemy selection
  start_enemy_select
when 1  # skill
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 1
  # Start skill selection
  start_skill_select
when 2  # guard
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 0
  @active_battler.current_action.basic = 1
  # Go to command input for next actor
  phase3_next_actor
when 3  # item
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 2
  # Start item selection
  start_item_select
end
Der XP verwendet hierfür die ID, die der Befehl innerhalb des Auswahlfensters hat (beginnend bei 0). Da wir nur noch "Skill" und "Item" haben, sind das jetzt die Einträge mit den IDs 0 und 1. Wir müssen das case-Statement also entsprechend umbauen:
Code: 
# Branch by actor command window cursor position
case @actor_command_window.index
when 0  # skill
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 1
  # Start skill selection
  start_skill_select
when 1  # item
  # Play decision SE
  $game_system.se_play($data_system.decision_se)
  # Set action
  @active_battler.current_action.kind = 2
  # Start item selection
  start_item_select
end