The required light level for crafting is a little high - I’ve never had a thunderstorm prevent me from seeing a foot in front of my face (while under shelter) before. Maybe different crafting tasks should require different light levels? Specifically: a thunderstorm might prevent you from making clothes or soldering because you can’t see exactly what you’re doing, but it definitely won’t prevent you from hammering some nails into a piece of wood (i.e. nailbat). A very skilled craftsman (level 9-10) might even be able to perform simpler tasks blindfolded.
Also, atlatls. I’d try to add this myself but I can’t find definitions for bows in the jsons OR the code itself.
While I’m on the topic of ancient weaponry, shields? Probably only very rarely found in pawn shops, or museums if they’re ever added. Could also have recipes in a book (that one armormaking thing?)
Scutum or tower shield - must be wielded; adds a large speed penalty and blocks a large majority of attacks (esp. ranged), but prevents the user from returning fire unless they take the time to drop the shield. A survivalist version might have spikes so as to be set into the ground to provide temporary cover (as a construction?), or worn on the back to act as weak torso armor.
Kite? shield, riot shield, buckler, two-by-shield - equipped on arms; provides both encumbrance and chance to block attacks in varying degrees.
Of course, none of these would do anything against a turret. 
On the topic of ‘distilled mutagen’ - isn’t there at least one item (tainted tornado) that serves that purpose already?
