group email - I use send mail options: enable collect addresses across found set, and bcc. So they are collected for the found set; no issues with member deletion.
the alternate is to loop the found set and collect to variable ; e.g. when his and hers emails exist... or multiple parents etc.
For sending individual emails, I create PDF attachments (e.g. invoices) if these need individual member inclusions, saved into container field; via a loop script.
A loop and send could be used to send individual emails with individual customised attachments, but user input required; on my short list of things to find a better method for.