Basic setup requirements for Assist using IOS only

So I’m super late to the Voice Party, but just beginning to dabble with it. I am a long time HA user with a robust (and fully functional) HA system, so not a noob to the platform, just a noob to voice commands.

I’d like to get a better understanding of exactly what I’ll need to simply issue commands from an iPhone and get a response. I have loaded both shortcuts and can get the built in sentences to work most of the time. Sometimes I get a DONE back, but the light does not turn on/off. I also tinkered with custom sentences, but can not get this to work at all. Full disclosure: I have not installed Whisper or Piper or the Wake word tool since I did not intend to use Assist throughout the house yet. Simply tinkering with iPhone control at the moment.

So my questions are:
Do I need Piper and Whisper at this time?
Do I need Piper and Whisper for custom sentences?
Am I missing some other component?
Can HA respond to iPhone with Siri SPEAKING the response, or is it just the returned text?
I’d like to keep my Assist code in an !include file. What is the proper way of doing this? See below.

# ******************************************************************************
#    Included Files
# ******************************************************************************
alarm_control_panel: !include includes/alarm_cp.yaml
anniversaries: !include includes/anniversary.yaml
automation manual: !include_dir_merge_list automations
automation ui: !include automations.yaml
# ^^ uses both the UI editor and YAML mode
binary_sensor: !include_dir_merge_list binary_sensors
camera: !include_dir_merge_list cameras

Possibly
intents: !include custom_sentences/en/intents.yaml and
intent_scripts: !include custom_sentences/en/intent_scripts.yaml

And finally, is the following code proper? It is located in my ‘automations’ folder and the referenced scripts work perfectly in my code. I have not been able to get these to work via the iPhone.

#################################################################
## CONVERSATION INTENTS AUTOMATION
#################################################################
#
#############################################################
#   Intent: Disable the Alarm
#############################################################
- id: intent_disable_the_alarm
  mode: single
  alias: Disable the Alarm
  description: Disable the Alarm
  trigger:
    - platform: conversation
      command: Disable the Alarm
  condition: []
  action:
    - service: script.turn_on
      entity_id: script.set_alarm_disarmed
#
#############################################################
#   Intent: Open the Garage Door
#############################################################
- id: intent_open_the_garage_door
  mode: single
  alias: Open the Garage Door
  description: Open the Garage Door
  trigger:
    - platform: conversation
      command: Open the Garage Door
  condition: []
  action:
    - service: script.turn_on
      entity_id: script.unlock_garage2

Any help would be appreciated. Thank you.