Fire Emblem Fates: Laying the groundwork

[Dark Holy Elf]

Mozu has access to the Kodachi/Throwing Club anyway.

There are three Bolt Naginatas, two from the shop and one in a chest.

I basically agree with your assessment; I think the Bolt Naginata is okay to allow (especially since its lower-power makes it rather corner-casey) but I do think it's worth acknowledging than it is on shakier ground than the other route-appropriate magical weapons (Conquest's sword/axe/bow and Birthright's shuriken).

[hinode]

My kneejerk is to allow it but not let it hit weakness/get press turns/anything besides just "range 1-2" or "do magic damage"; just treat it as non-elemental damage, basically. Spoiling someone like P3 Aigis is the super niche corner case that (a) would make it more desirable for the lance using cast at large and (b) feels kinda cheesy.

Tempted to do that with all Fates magic weapons actually, unless there's a compelling reason to treat them as elemental that I'm missing.

[Dark Holy Elf]

The cast (especially Maid!Felicia, and also FE13 Anna if you extend it to her) would probably be pretty happy with you if you treated the magic weapons as non-elemental, and given that elements aren't actually a thing in this game (even less than most FEs, there's no "magic triangle" and no element-based weakness hitting like Tellius/Awakening) if you want to vote that way there's really no evidence to argue against it besides flavour.

It's even weirder in Fates than most because you get all the "spirits" (Hoshido magic) which are the equivalent to tomes but have no elements associated with them, just an animal and colour.

[hinode]

I'm totally okay with an interp that makes magic weapons better for people who actually rely on them in the DL in general and worse for the people who'd only care about fishing for press turns on Persona 3/4 PCs. That feels like it reflects the in-game value of said weapons better.

And yeah, the complete lack of elemental properties even by FE series standards factors into my thinking.

[SnowFire]

Well, Fates and Awakening do have ONE element that stands out: Dark.  Just for reasons that aren't resistance / weakness.