Does anyone know if you can add a spouse to an existing 401k?
I was told that you can't and that it is the law. I am in Hawaii and not familiar with that.
If this is correct, any suggestions besides liquidating and eat penalties and taxes to have both my wife and I on the same account. Roth, IRA's etc.

When you say "add a spouse" - do you mean add her as a beneficiary, or as a co-owner? By law, your spouse is automatically a beneficiary (unless she gives approval in writing to not be the beneficiary). But there can be only one owner - so if that's your question, then no, you cannot "add" a spouse as a co-owner of your account.

Why do you want to change the ownership anyway?