Draft: Change the representation of unit types

[LuminaSapphira]

This was previously fixed though its merge highlighted several issues that have yet to be resolved. See discussion at the following locations.

#43 #82 #96

This is the new PR to fix this which helpfully already includes the necessary 'revert revert' commit.

[Lucretiel]

Per #96, it seems like the relevant types should be name?: null instead of name: null; was that reverted deliberately?