Does redirect work on inactive mailboxes?

[Calum_L1]

I'm working on a complex merger process where I have inactive mailboxes (unlicensed) but I need to redirect incoming email to another tenant. 

In other words I have the mailbox fred-at-contoso.com which is inactive with a hold, but doesn't have an Microsoft 365 license.

Can an email redirect without retaining a copy be added to fret-at-fabrikam.com be added to this mailbox?

[#2]

Inactive mailboxes should be excluded from transport processing. In your scenario, you can simply create a mail user object with the targetaddress pointing to the email address removed for privacy reasons adddress.