the objects that display black are because thier normals are reversed but what caused it is the freezing of transforms, i'm guessing that they were mirrored geo with a - scale value.If you freeze transforms on mirrored geo you will see a warning the the opposite attribute will be set and could cause problems (hence the reversed normals).To solve the issue of further problems down the line i.e wierd scaling select the geo that is black and hit ctrl + A to bring up the attribute editor and go down to the Render Stats tab and uncheck Double Sided followed by unchecking Opposite then rechecking Double Sided. you can now reverse the normals if needed and all will be fine.
If you mirror geo and do not combine and merge verts (in other words leave it as it's own object then this will always happen if you freeze the transforms, it is not an issue if you combine and merge with the other half to make a whole object.