In chapter 2 of HotU, I'm trying to spend some money to upgrade my companions' weapons with the smith. As I'm a mage, though, I can't equip the weapons to tell him to upgrade them. Short of giving all my NPCs staffs and daggers/taking a dip into fighter/spending a bunch of feats on proficiencies, is there a way to get the weapons to upgrade? I don't have any objection to using mods or, if necessary, using the console.

Well, you could export the save file of your character from the end of chapter 1, give him all weapon proficiency feats with the gff editor, and just play nice and don't use weapons your character shouldn't have access to.

GFF editor can be found with google or on the vault probably.

Open the .bic file with your character. There's a featlist section that can be expanded. Each entry you add is room for a feat, each feat has a numeric code. I don't have a list of the feat codes for nwn1, but in 2 many have similar codes I think and that's the first google result for "nwn feat list."

My 2c.

Well, if you don't mind using the console, you could level yourself up until you can take Martial Proficiency, get the weapons enchanted, then drop yourself back down to the initial level. Just keep in mind the exact XP you started at.

Many custom modules (like the Aielund Saga -- which, incidentally, is far better than any of the official campaigns) allow you to specify someone else as the target of the enchant which avoids the problem.

Doesn't that end up screwing your progression up though, making you not just have the extra feats but other outside of rules advantages? BAB/saves/slots/etc? Never really tried it.

As long as you use the console to reduce your level afterwards you're fine. When you reduce your level through the console it rolls back everything; feats, skills, BAB, and class features. The only thing you need to be mindful of is the Red Dragon Disciple, which can bug up if you level it down.

For future reference, there's a mod for just that buried in the depths of the Vault: https://neverwintervault.org/project/nwn1/hakpak/hotu-smith-fix