Edit: The link provided by @broken headphones has helped resolve my する/している problem (I think). I have one problem remaining though. Given @Sonny365TANAKA's answer that 彼女は長い髪の毛です is not grammatical, if 田中さんは神妙な顔だ is grammatical then what is the difference? Translating directly to English, why can I say "Tanaka is a meek face" but I cannot say "She is long hair". Both describe a person's features and both sound strange to me.
Tanaka has a meek face.
Describing facial expressions confuses me. Firstly because of the use of "is" rather than "has" i.e. literal translation of the first sentence is "Tanaka is a meek face". I can live with that.
Is there any difference in meaning/nuance between these two sentences. How do I interpret している? Is it "is making", "has made", or simply "is/has".
Does the way I phrase it change depending on whether I'm talking about the current state of the face or an enduring feature. e.g.
Tanaka has a meek face (and it is always like that. It's just his character)
Tanaka has a meek face (because he's just done something shameful)
Am I right that these issues occur with other aspects of describing a person? For example I saw these two sentences in some example translations:
My instinct tells me that the second one is incorrect even though that is how you would expect to translate it.