I think the "12" means they run at nominal 12V. Why did you choose these? 6V and 3V versions are available.
What are these for? I guess one might be to make 3.3V for the blue pill because it's regulator can only accept up to 5.5V, but it seems overkill for that.
I think I would have chosen one type only, for simplicity, but should be ok I guess.
I guess you can add this later, but leave it out for the moment. Lots to get working before this becomes useful.