Where do you draw the line for “alternative rules”? Because my house rule (and if allowed hopefully a project to put out on Drivethru) will allow knives for mages since they are actually part of the starter kit for that class, and then ADD reasons to why. As in “it’s made of a nonferrous metal and it doesn’t hamper casting”.Alternative rules are not allowed under the license, no, even if "optional".Will optional rules ok? For instance, hypothetically an alternate means of handling parry that leaves it to the GM and players to choose whether they use them or not
New schools of magic or additional skills?
New secondary skills, including magic schools, are totally fine. You cannot add or remove core skills.
And further, adding what is practically an enchantment for mage weapons only, giving mages the ability to wield such weapons. Is that changing lore or adding, in the style of “mages can’t use metal, unless blabla”?