I have a custom og:image meta property in my header that links to https://daks2k3a4ib2z.cloudfront.net/54a0d8...etc… I have redirected the ARecords so will these links change? How about any custom links in custom code?
Nope, your site will function normally (but much faster) after the DNS changes.
I wondered if the cloudfront.net portion of the URL would be changing as I was thinking that was part of the CDN with Amazon and now that would all be with Fastly.