I need someone to migrate and merge one Office 365 tenant with another.

I have had a business merger.
I now have two Office 365 tenants.
I want to move the smaller tenant into the larger tenant.
The smaller tenant is 11 active users.
All these users have mail. There is also some historical shared mailboxes.
There is also quite a few teams groups and a sharepoint site.

I want to end up with all the users in the same tenant.
I want all users to keep their existing mail.
I want all the sharepoint sites to remain.
I want the teams data to be retained.
I want all items in the larger tenant to remain untouched.