In some situations, I don’t think it’s possible to join arrays to arrays, but I think you could do it if you first create a Joined List column with a comma delimiter to replace the Lookup column, then create a Template column to join your individual sheet columns into a comma delimited list, along with the Joined List column. That should give you a comma delimited list if all emails combined. Finally you can create a Split Text column to turn that template column back into an array.
Edit: Missed the part about wanting to use this for row owners. Definitely not possible for that use case.