It's Greek to me

A stock objection to the historicity of some dominical statements is the claim that they rely on puns or double entendres which only work in Greek, yet Jesus normally spoke Aramaic. One example is the use of anothen ("above", "again", "anew") in Jn 3. I've discussed this before, but I'd like to make some additional points:

i) My post is not addressed to hardline skeptics. My immediate aim is just to consider whether the narrator slipped up. Is Jn 3 internally inconsistent or anachronistic? Did the narrator neglect to consider what a realistic conversation in that setting would amount to?

ii) Do we have a representative sample of 1C Aramaic? In addition, the types of ancient language that are apt to be preserved are official, literary, and/or legal texts and inscriptions rather than vernacular. Colloquial usage is underrepresented. 

iii) Since Nicodemus initiated the conversion, it would be in whatever language he used at the outset.

iv) As some scholars point out, he has a Greek name, so he may well be polyglot. 

v) As the Son of God, Jesus knows every human language. His divine consciousness can share information with his human consciousness on a need to know basis. 

A critic might object that this begs the question. However, I'm just discussing whether the account is inconsistent, not whether it's factual. From the narrative viewpoint, Jesus is omniscient. So the account can't be faulted on those grounds. 

vi) Sometimes two polyglot conversation partners who are with a group of people will speak a language the two conversation partners understand but the group does not. They don't want everyone within earshot to know what they are saying to each other. Using a language only they know preserves the secrecy of their communication. 

vii) Apropos (vi), at this stage, Nicodemus is noncommittal. He's intrigued by Jesus and impressed by Jesus, but he hasn't made up his mind. He has some questions for Jesus. Questions about Jesus that he brings to Jesus. 

He comes at night to be discreet. One or more of the disciples were probably in attendance when Nicodemus came to see Jesus. He doesn't want the disciples to eavesdrop on the conversation. He doesn't wish to fuel gossip or rumors about his interest in Jesus. At this stage of his investigation, it's premature to stick his neck out. Later he will be bolder, but at this preliminary stage, he has some questions he needs to settle to his own satisfaction, by taking his questions about Jesus straight to Jesus. How Jesus answers them, as well as subsequent developments, will be decisive. 

viii) A critic might ask, in that event, what's the source of this account, if one or more disciples who overheard it didn't understand. It's possible that Jesus explained it to them after Nicodemus left. Certainly they'd be curious. Mind you, that might be breach of confidence. 

Or Nicodemus might have recounted the conversation to the narrator (the apostle John/Beloved Disciple) after Nicodemus became a convert. 

Over and above that is the general phenomenon of the omniscient narrator in Scripture. Unbelievers regard that as a fictional convention. By contrast, believers attribute that to inspiration or revelation.