I repaired each of the broken items in the game and corrected the existing store inventories so that you can purchase the corrected items. This process involved modifying a iprp_feats.2da file (which should be able to be safely merged with any other mod - I picked a very deep, random code), replacing the bugged property with a functioning version in various item blueprints, replacing the item in each of the shop blueprints that sold the bugged items, and writing a simple method to create stores from blueprints rather than requiring them to be tied into the module. They're still persistent, with the same buy/sell ratios that respond to your Appraise skill, and are accessed through the same dialogue tree. It's just loading a different inventory.

After equipping any of the relevant items, Darkvision will appear in your mode bar regardless of race/class until the item is unequipped. As far as I am aware, it doesn't functionally DO anything other than make it easier for you (the player) to see in dark areas. But, now the items work. Existing items won't be changed, but newly spawned items will use the corrected blueprints and the next time you talk to any of the relevant0 merchants their store inventories will load the modified blueprints.

Installation is simple. Just unzip the file and put it in your Override folder. The Readme has a full list of changed/added files. If you need to merge the .2da, do so. There's just the one changed line, adding "Darkvision" to the list of feats that can be added to an item with the "Bonus Feat" property.

Uninstalling is just as easy. Pull it out of Override. It won't break anything. Existing items will remain, stores will refresh with their default inventories.