(CapsLock was remapped to Option in System Preferences > Keyboard > Modifier Keys because Model M) IMPORTANT: Change the Key Overlaid Modifier Timeout to 200ms.

private.xml

<?xml version="1.0"?>
<root>

  <item>
    <name>Change Option_L to Option_L (Send a Delete key event if Option_L is tapped alone)</name>
    <!-- Remaps Option_L to Delete if tapped, and to Option_L if held down or used with another key (e.g. Opt+Cmd) -->
    <identifier>private.optionL2optionL_Delete</identifier>
    <autogen>
      __KeyOverlaidModifier__
      KeyCode::OPTION_L, ModifierFlag::OPTION_L | ModifierFlag::NONE,
      KeyCode::OPTION_L,
      KeyCode::DELETE,
    </autogen>
  </item>
  <item>
    <name>Change Command_R to Command_R (Send an Return key event if Command_R is tapped alone)</name>
    <!-- Remaps Command_R to Return if tapped, and to Command_R if held down or used with another key (e.g. Cmd+O) -->
    <identifier>private.commandR2commandR_Return</identifier>
    <autogen>
      __KeyOverlaidModifier__
      KeyCode::COMMAND_R, ModifierFlag::COMMAND_R | ModifierFlag::NONE,
      KeyCode::COMMAND_R,
      KeyCode::RETURN,
    </autogen>
  </item>
  <item>
    <name>Change Option_L+n to ñ</name>
    <!-- Remaps Option_L+N to Ñ (enable "QWERTY to Colemak" to make it work, else press J instead of N) -->
    <identifier>OptionLplusNToEnie</identifier>
    <autogen>
        --KeyToKey--
        KeyCode::J, ModifierFlag::OPTION_L | ModifierFlag::NONE,
        KeyCode::N, ModifierFlag::OPTION_R, KeyCode::N
    </autogen>
    <autogen>
        --KeyToKey--
        KeyCode::J, ModifierFlag::OPTION_L | ModifierFlag::SHIFT_R | ModifierFlag::NONE,
        KeyCode::N, ModifierFlag::OPTION_R, KeyCode::N, ModifierFlag::SHIFT_R
    </autogen>
    <autogen>
        --KeyToKey--
        KeyCode::J, ModifierFlag::OPTION_L | ModifierFlag::SHIFT_L | ModifierFlag::NONE,
        KeyCode::N, ModifierFlag::OPTION_R, KeyCode::N, ModifierFlag::SHIFT_R
    </autogen>
    </item>
</root>