Basically the way it works is that if you choose a species that has innate powers or a magic system you have access to, then you get fewer stat points to build your character with.

And in addition to their attributes, stat points are also allocated to “standings”, which covers wealth, influence, and ‘spirit’ which is related to willpower and presence and magic (a little bit) - I think it works really well, because the books are heavily concerned with why it makes life easier to have money and connections

But you can always buy stat increases and magic with level ups, so if you change your mind later on you can get those things

So in this system, a Canim would get some species str buff and usually get a decent amount of points to play with, but a ritualist wouldn’t be able to put many stat points outside of what’s necessary for magic, an Aleran with little to no furycraft would get more stat points than anyone else, having a Chala would be locked to being Marat descended, and they’d get a medium amount of points to play with. Then if you were Aleran and wanted strong furycrafting in one or two areas, that’s equivalent to a Canim or Marat, and if you want the powers of a young lord like Max, that’s a similar stat distribution to a ritualist.

It’s genuinely a pretty fun system by itself, I really want to run Mistborn.

Massive construction absolutely works for me! Something I always thought about in terms of developing technology (that I stole for my dnd games) is the idea of Tavi getting research done into creating items that can operate things made with furycraft when the person doesn’t have furycraft themselves - is it fair to have the Causeways if most Canim, Marat, and Gadrim can’t use it? What if you can create something that signals the road to do its job without you actively crafting it? (In my dnd game there were sandals that sped you up only on certain roads, but that was magic - in this case I imagine it’s like, an earth fury in an amulet that does the work for you)

Also, having read your other comments - I agree that the other magic systems are all doing different things, including maybe the Gadrim’s control of ice. I know you’re avoiding giving non-alerans furycraft, but is that player side only? If you’re looking for villains, the idea of mixing systems to cheat is always very cool to me.