Rolling out: tenant admin tools to connect existing SharePoint team sites to new Office 365 Groups

Kevin Beckett - the global admin tools (e.g. PowerShell cmdlet and API) are being pushed to GA, and can take a few days to fully appear in all environments.

On your other questions:

1) If keeping the old homepage - is it a classic page?  Or a modern one?  The primary reasons for adding a new home page to the site are:

- you get the latest home page layout

- it's modern, and you get all the benefits of page authoring, web parts, etc

- you get all the group connected benefits on the page, including group metadata in the header (e.g. privacy, classification, group membership, group info via group card) and left nav (e.g. link to group conversations).  

- includes a link to the previous home page as a sub-node to the 'Home' node in left nav

If you already have a modern page as your homepage and like it, you can always delete the home(1).aspx page.  But fair feedback.   

2) We're looking at ways to preserve the original site logo as the group's logo, but don't have this feature yet. :)