Melonbooks has a bonus pamphlet that comes with the book, it has a few 4 panel comics that are pretty fun. I couldn't find any scans online, and I don't have a scanner myself, so if you're interested you're gonna have to buy the book yourself (
https://www.melonbooks.co.jp/products/detail.php?product_id=2559865)
Also, a few of you know this, but the first manga I ever translated was these Futaribeya side stories, almost exactly a year ago. It feels nice to finally redo this mess. I'll update the chapters under the original oneshot entries as well sometime soon.