About number 3:
They could decide to go to court to file for copyright infringement where, yes, their name would go into court documents. However, no one has ever said the developer didn't want their identity known (if so, please point to where you read this)...
People have a misguided belief that "Kyle" hides his identity to prevent online harassment or physical altercations over this game. As if this game is the only thing that matters in the world. It's just sad.
Another possibility is that he would be shunned by his family or his community over this game or its contents (especially if it's based on real people or real events). But unless they would specifically go to court or follow this case, they would probably stay completely oblivious to it.
And unless porn is not legal in their jurisdiction (even fictional), they wouldn't have a reason not to go to court.
The only reason is laziness. But since it's essentially more free money, there's really no reason to avoid going to court.
If you were found guilty of copyright infringement, you'd then be responsible to pay all court costs, your attorney fees, their attorney fees, any fines and financial compensation that the court determines in his favor. Even if you were found not guilty - you'd be responsible for your attorney fees.
Don't know your point of your post - but it's obvious you weren't aware of even three of the possible actions the developer could take if they decided you were infringing on their intellectual property.
IANAL and I don't know the intricacies of US court systems, but just to clarify: Could gumdrop establish a trust and assign copyright to it, then the trust would be the one to fight the copyright case? He'd still retain his anonymity, so even if he wanted to, that point would be moot.