Multiple Legacy Exchange Forests -> Single Office 365

I currently have 2 legacy Exchange forests:

• legacysales.com
• legacyservices.com

Both of these organisations are being migrated to a consolidated Active Directory:

• newsalesservices.com

The new organisation will use Office 365. There will be no On-Premise Exchange in this organisation.

My challenge is to migrate to new AD and Office 365.

I can't find much info on this so here is my proposed plan:

1. Configure hybrid deployment in legacysales.com with newsalesservices.com Office 365 and migrate mail.
2. Configure hybrid deployment in legacyservices.com with newsalesservices.com Office 365 and migrate mail.
3. Migrate AD user objects from legacysales.com to newsalesservices.com on-premises AD (use ADMT, retain SIDs etc.)
4. Migrate AD user objects from legacysales.com to newsalesservices.com on-premises AD (use ADMT, retain SIDs etc.)
5. Use new Azure Active Directory Sync (AADS) to sync from new AD user objects in newssalesservices.com AD to newsalesservices.com Office 365 (match on different attribute e.g. legacy mail address).

Does anyone have any experience with a similar scenario? Any caveats? Any feedback?