I've been reading through dozens of threads, plugin posts, SO posts, etc. over the past few days and the main takeaway is that this is a feature much desired by many users, and has been so for many ~7 years already.
Plugin "downloadMyFiles" is the closest that comes to doing what I want, but given that it has not been updated in a year and doesn't even have a config.xml file, makes me rather sceptical as to whether it will be updated in the future and remain usable.
As for the link you posted, thank you for the reference. What I dont quite get here is how I am supposed to do this for 15-20 images that I want to upload via one file-upload question. There has to be a better way to capture those images, perhaps move them to a public folder with a matching SID, and then add it to the email notification.
The link you shared deals with uploading and displaying a single image during the ongoing survey, so not quite what is needed for my specific case.
Honestly, at this point I am considering moving my surveys to Surveymonkey simply because of this one functionality. I really wish LS would come up with a way to make it easier to share uploaded files with external users, data privacy should not be the reason why this gets canned.
Thanks for the help though, if there is any plugin or other way of doing this, would appreciate a link.