"Low magic" is completely a matter of presentation. You can use all the core D&D material, and let the PCs play whatever classes they want, and if you make the NPCs treat them as rare and unique, the world can still seem low magic.
The real world is low magic, but in Egypt you have stories of gods bringing each other back from the dead, of great plagues of locusts and fire and death, of pillars of fire and partings of seas. And occasionally of Scorpion Kings (but that's unconfirmed).
The thing is, if people's everyday lives don't involve much magic, it makes the magic things more spectacular. The campaign saga includes two magical schools. In core D&D, those are like colleges -- people join, learn magic, and are otherwise normal. In your setting, just change the flavor a bit -- it's an occult group who frighten away the common folk, and though there are only a dozen students out of an entire city of thousands of people, and though most of the students can't even cast a fireball, the populace treats them with great respect and fear.
The setting, as written, is about as high in magic as Lord of the Rings, with the one exception of the mile-long living airship. In everything else, the magic is not obvious. You could easily say people would rarely see it. But low-magic usually just means that people don't use magic very often. There are still magical monsters, places of eldritch mystery, and myths that lie sleeping, waiting to return to the world.
All you need to do is make sure the town blacksmith doesn't use cantrips.
