darrenSP - You can easily update the confirmation message from a text editor. 

Below is the text key used for show Thanks for your feedback message. 

page.RatingEnumerationDisplay.feedback.success.title

Studio -> Text Editor -> Community Text 

Lithium uses the text key for each string appearing in the community.  You can search for the string you want to update from there. 

https://community.lithium.com/t5/FAQs-email-templates-and-text/About-text-keys/ta-p/109029

https://community.lithium.com/t5/FAQs-email-templates-and-text/Find-text-keys/ta-p/109027

Regarding the custom component for this, there is no POST API call available for helpfulness, you can only perform GET action. 

https://community.lithium.com/t5/Developer-Documentation/bd-p/dev-doc-portal?section=commv2&collection=tkb_helpfulness_ratings#constraints-message.id

Hi! I asked a very similar question recently, but regarding  group hubs. See the accepted solution there, I believe the answer for you is the same!Is it possible to have group hubs with different landing pages? 

Hi bishalgoswami,

The quilt for the My Settings page (as mentioned by CarolineS) is called MyProfilePage.  However, the primary functionality of the settings page is handled in an out-of-the-box component called "tabs" which is not editable in Studio.

In my environment where I wanted to make changes to the settings page, I created my own component (which I called "custom.user.settings.tabs") where I first rendered the out-of-the-box component while wrapping it in my own custom div so I could make CSS-based changes, as shown below.

<#-- Render the out-of-the-box component -->
<div class="rsa-c-user-settings-tabs">
  <@component id="tabs"/>
</div>

I then used the <@liaAddScript> functionality to add jQuery to make other changes I needed, such as hiding the ability to change their email address or first/last name.  See the screenshots below.

Hope this helps!