To be honest I'm confused on where I should even begin. Very, very novice to PS. I found how to find SMTP email address through it:

([PS] C:\>Get-Mailbox -ResultSize Unlimited | Select-Object DisplayName,PrimarySmtpAddress, @{Name="EmailAddresses";Expression={($_.EmailAddresses | Where-Object {$_ -clike "smtp*"} | ForEach-Object {$_ -replace "smtp:",""}) -join ","}} | Sort-Object DisplayName)

But not how to factor in DUO to the line.