With Lore 5, making base item strength 5, and then spending 7 more slots to up the power to 12,  is there any reason I can't have a weapon:6 item with no limit to number of times used?

If so, why would a wizard ever need to use a damage spell? For 2 refresh you have weapon 6 item that doesn't require stress. You could get the required 8 item slots from channeling and ritual meaning that (other than the Lore 5 requirement, which can be fixed upon earning your first skill point) an "Up to your Waist" character could start the game with this.

Furthermore, as the warden sword, an enchanted item, gets around the First Law, would said weapon:6 enchanted item also not be subject to the First Law?

Thanks in advance for your help.