Bug holes has 2 short actions in stock with mag bolts. Probably could trade for, or buy a .223 bolt and sell the mag bolt.
http://www.bugholes.com/product-p/z-origin-sa-mag-r.htm
This is impressive. The chamber brushes I have would require a sledge to beat them through the barrel. How in the world did you get it through the barrel.
https://redhawkrifles.com/remington-700-bdl-internal-magazine-box/
These guys have some in stock. I ordered a Long action internal mag from them a couple of weeks ago. Received it quickly.
This checks a lot of boxes. You could probably pop that pink part off and us the cup as a dip spitter in a pinch. Side note...That’s the weirdest tervis cup I’ve ever seen.
https://bighornarms.com/product/bolt-head-1
Zermatt has a few left if you still can’t find one. Just got one in today. Only took about a week to get to me from Zermatt.