* The devs will say it's technically impossible to give him access to those funds. They will be hoping that nobody understands bitcoin well enough to prove that it is in fact possible in a way that a court can understand, and they will try to create confusion in the hope that everybody will give up trying to understand.
* Wright named the Bitcoin SV developers as defendants for precisely this purpose. He will release a new version of the Bitcoin SV code that has an exception to the transaction verification rules for a single transaction paying from the 1Feex address to an address that he controls. The exception to the transaction verification rules will *not require a valid signature* from the 1Feex address. That transaction will be hard coded into the source code. It will be regarded as valid automatically, without a signature check.
* He will say to the court: Look, it is obviously possible. I did it. The Bitcoin Core devs can do the same thing.
...
It is not "technically impossible", but it is practically infeasible.
He doesn't even need the Bitcoin Core devs to make changes to Bitcoin Core. He can fork the repository and make the changes to Bitcoin Core himself. Then, he can use his version to claim the bitcoins from those addresses himself. Nobody will care because he will be on his own fork of the Bitcoin chain as soon as he does that.
In order to succeed, the court must order the owners of every node in the world (including miners) to use his version of Bitcoin Core. That is practically infeasible.
Bitcoin SV is a different situation. I don't think he will have any problem getting the changes into the Bitcoin SV reference client. The question here is, will users (especially exchanges) follow his fork? They might, but he will have the same problem as with Bitcoin Core if they don't.