JackWallet sounds nice. It sounds catchy. Also it's sort of like a car jack is to a car. You use JackWallet to repair your wallet!
I don't think people will value a software to deal with their private keys if its name makes them think about car-jacking.
I'm not an English native though so maybe it's catchy and not scary. If so, could native speakers tell me so?
I don't see a problem with JackWallet but English is not my mother tongue, so you might want to wait for more people to provide you with an answer to your question.
How about JacquesWallet then?
JWallet is already taken and could imply your fork is written in Java so I'm not going to suggest it.