Heh, I feel a bit reverse bamboozled, the death flag was so obvious that I actually didn't believe it and thought "author is just playing with us subverting the trope" but then no, played straight. It might be a bit cliched but still done reasonably well for a solid finale. The conspiracy seems fittingly down to earth and small which actually works here. Agreed that as far as dying goes this would be a pretty decent way.
Eh, on the scale of rigged stuff seems reasonable to me. Simple suppressors are cheap and easy to make and in turn easy to fake, are large, have lots of volume, can be made with a variety of materials and since it's modular he'd still be able to use the gun by just not putting it on. A fake suppressor could easily have not just the camera in there but also battery, cellular/aggressive wifi and quite big antennas around the can so that it'd have decent connectivity even indoors. And as a hiding place it's actually kinda clever in some respects against those who are used to guns, because one of core things you learn as an ingrained habit is never ever point the barrel at anything you don't want to destroy, let alone look down it yourself. Just running in the flow I can easily see that being a total blind spot for experienced gun users more then anyone.
The only stretch is anticipating needing it ahead of time. But I can see that being on the edge of believable, since again having a rigged suppressor doesn't interfere with use of the gun, or even having another regular suppressor on him as well. So it doesn't restrict his options if he's been supplied with both just in case, and "we should have something to spy with if you do get caught that won't get found" is something an agency like this might think of. It seems gudenuf for this series which has plenty of much bigger stretches then this lol.