In the rules it says that "During the "death wait", the only darkness ability available will be to view CPs." Does this mean that CPs transfer over to new characters and that you can vote during your death wait?
Yes; CPs are OOC currency, rather than something you can use in-character, and are received for helping the Combine out OOC. As such, they do transfer to your character. I'm not sure what you mean by voting, but if you mean the deathmatch, it tends to stay up for longer than three weeks so either way you shouldn't have any trouble voting.