We have announced that Group Owners will be able to leverage existing groups to drive membership in Office 365 Groups.
We are working on providing the ability to change the email address (both primary and secondary) associated with a group.
Roadmap item: https://products.office.com/en-US/business/office-365-roadmap?filters=&freeformsearch=27891&featureid=27891Anonymous commented
Office 365 groups are recommended in place of distribution lists, but they have two important limitations: they can't have aliases and they can't be members of another distribution list. The latter could've been used as a workaround for aliases, but even that is not possible.