customer notifications and Domain authentication

Hello Community - Having spent the last 3 days with shopify advisors and sidekick am starting to loose hope in this platform. I need a few basic things edited prior to going live, Despite many many many efforts cannot seem to get it to work, is there anyone that is able to assist with the following pretty please..?

  1. ‘New Gift Card customer notification’ - The logo needs to appear at the top of the page, centre aligned. Above any and all text, the text to follow and then the gift card.
  2. Instagram and Facebook appear as the words - Id like them to appear as the icons.
  3. I repeatedly receive the notification that my email domain hasn’t been authenticated - I have authenticated my domain many times and received notification that it is complete yet still receive the following message: - Because your email domain hasn’t been authenticated, recipients will see your email as store+79256650000@shopifyemail.com. For better brand recognition, authenticate your domain and ensure your domain has a DMARC record.

Please advise.