Yes, you can cook for iOS on Windows (and the Cooked-IOS directory could be copied across). One exception: Windows cannot compile Metal shaders offline, so you will have a slower load at runtime.
I am curious as to why it’s so slow to cook on the Mac? The usual cause of this was texture compression using high quality mode on Mac but low quality on Windows, but that was fixed in like 4.2 or 4.3 (where a setting was added to the Project Settings to control the compression level for PVRTC textures, defaulting to 0, the lowest).
Josh