Google Platform Optimization including email domain Migration

Please do not call or email me directly.

Goal: Change from Google for NonProfits to Google Business Standard or Pro to take the most advantage of what Google offers because it's our base software.
Tasks:
Before we switch, I want to reduce the number of users we have. We have 2 domains:
eodsa.ca and eosoccer.ca. The former is an old domain that still has active email accounts. I want to transfer all of those emails to the new eosoccer.ca addresses - role to the appropriate role.

When I try to migrate the emails, the email going to the 'From' address is blocked, saying that the domain has an issue. I need that fixed.

Once all of the eodsa.ca emails have been migrated, they need to be deleted.
When that is done I'll review the users left and see if I can remove any more.
Then I'll switch to a Business profile.

IN ADDITION: I'd like to look into Google Voice. We currently use Fongo. It works well but I want to reduce the number of platforms we use. We need the option to text recipients, send voice mails to our cellphones, voicemails to email. I need help figuring out if Google Voice will work for us.