Ah, you can step up the weapon die to after using a d8 weapon. The maximum would be a d12 for a weapon die.
As for the magic items these were just the ones I came up with. If magic spell books makes more sense to you then hack it! 😀 add those in and let me know if the seem to work better for you. I may expand the weapons, gear and supplies but I just haven't been able to get back to Moss Cloak recently to add or revise much content. But I highly encourage homebrewing your own gear, supplies, weapons, and rulings.