This sounds really interesting. I’ve not done much with sheet scripting other than copy the odd script. But I am wondering if you could still use a social bookmarking service, say pinboard, then use IMPORTFEED in your sheet to grab all the links, and descriptions . This might be easier than opening a google form every time you want to add a link? Or not YMMV.
But you could then automate the creation of the newsletter as you outline above. Pinboard would be goods as you can get a feed for a tag (newsletter).
I am therefore thinking of creating a script in Sheets that collates all the links for the month in a Google Doc. To be honest, Google Apps Script is all still new to me, but I am wondering about the possibility of creating a template with merge fields. I remember Autocrat doing something similar. I could then use this to post in WordPress.