Tweak the Team Newsletter for use as a branded roundup newsletter
I suggest you tweak the Team Newsletter so it can be used as a roundup newsletter I share with my clients. Perhaps users could customize the template to add their company logo. Then the annotation and commenting features you already have could be used to make the roundup and brand the curation work.
Do emails sent to non team members get sent blind or do all who receive, see all addresses to whom it has been sent?