Plan a full domain name change and rebrand migration

My client is rebranding from [oldbrand.com] to [newbrand.com], and as part of the
rebrand the marketing team also wants some URL slugs updated to match new product
names (so this isn't a pure 1:1 domain swap, some paths change too). The site runs
WooCommerce and uses Google login for customer accounts.

Plan this migration end to end, reasoning through what a plain domain-swap checklist
would miss because slugs are also changing:

1. Redirect mapping: since not every old URL maps to the same path on the new domain,
   explain how to build a full old-URL-to-new-URL redirect map (not just a blanket
   domain-level 301) so link equity and existing rankings transfer per-page instead of
   everything just redirecting to the new homepage.
2. Serialized data and domain replacement: how to safely search-replace the old domain
   across the database including inside serialized arrays in page builder content,
   widget options, and WooCommerce order meta, without corrupting anything (a naive SQL
   REPLACE on serialized data breaks it because it doesn't update the stored string
   length prefix).
3. Third-party integrations tied to the old domain: enumerate the specific places the
   old domain is baked into external configuration that will silently keep failing
   after cutover unless updated, the payment gateway's webhook URL and any OAuth app
   redirect URI (Google login will break for every customer if the redirect URI in
   Google Cloud Console still lists the old domain), and analytics/Search Console
   properties that need a change-of-address submission, not a fresh setup.
4. Email continuity: if email addresses also move to @newbrand.com, explain how to
   avoid breaking WooCommerce transactional email deliverability during the switch
   (SPF/DKIM for the new domain must be live before outgoing mail starts using it).
5. Sequencing: give me the actual order across DNS, redirects, OAuth app updates, and
   search property change-of-address so there's no window where Google login is broken
   or a webhook silently fails.

For every integration you list, tell me exactly where in that third party's dashboard
to find and update the old domain reference.