Is it safe to delete the Android folder?

Yes, it is totally safe to delete empty folders in android. If your system required those folders it will automatically create those folders for you in the future. If you use some apps in the past and now you are not using them then those apps also left some empty folders so you can delete them as well.

What is face on my Android phone?

It’s the cache for face recognition used by the Gallery app. You can turn it off easily in the app’s settings. They’re not exactly hiding the feature… no need to be alarmed.