There's a set - The Dragon Ninja set - that turns all shuriken into Stamina-based ranged attacks instead of ammo-based ranged attacks.
If you combo that with plenty of "ranged x2 damage chance" till 100% and up your shuriken damage as well then you can play a shuriken ninja if you like.
The Dragon Ninja set can be found on Revenants in the last level, they'll be divine quality.
The Dragon Ninja set probably also drops from someone - you can probably look that up on the Wiki.
For Onmyo magic there's no 100% infinite spellcasting so far as I know, but you can stack infinite Onmyo on your gear and you can craft and keep some of those brushes at hand to refresh spells on the go, so you could do that.
I do think that being able to go melee in this game is pretty essential, especially early game since there's no way you'll get enough stat-boosting aspects on your equipment early on to support a ranged build.