This is probably best done by emitting an AutoAutoSave trigger token (and having AAS installed). Added to the notes.
No promises on any of these, but some initial thoughts:
Vision -- There isn't really any mechanic for making upgrades more or less common, but I like the idea.
Mini-Bandolier -- Bandolier is already so fragile I'm reluctant to add anything that might interact with it (and have considered removing it entirely, or making it off by default)
Unnamed -- unlikely; fiddling with ammo consumption works fine in vanilla doom/2 but has a lot of bad mod interactions
Ricochet -- it is impossible to reliably detect hitscan shots that miss (note that things like HE Shots proc only when they hit an enemy), so no.
Extender -- similarly, it's hard to reliably detect "the player has picked up an item" because the event can get "eaten" by other items in the player's inventory (or special handling on the item itself) before GB gets a chance to see it.
Tendrils -- a cool idea (shades of the Quake II BFG, a personal favourite) but as written it's also ridiculously overpowered, amounting to a 4.5x DPS increase and added AOE. I'd be more inclined to (and have already been experimenting with prototypes for) make the tendrils do something other than damage, like sticking enemies together so that they are more vulnerable to splash damage.