Do you have a convention for using import typing vs. from typing import ...? If so, could you switch to that convention across all these type annotations?

No conventions, some types are better import from typing_extensions to ensure backward compatibility in which case I prefer the from typing import ... syntax to easily switch between those.

Does dict assign the same type as Dict?

Yes, we still support 3.8 but later versions of Python prefer using that with the list[int] syntax.