Yes, carry in Henderson parks is ok. Make sure it is a Henderson City park and not a county park within Henderson.
Las Vegas abolished their law and wrote a new one. This is not legal under state preemption. So, you will be arrested and taken to jail. If you get a lawyer and fight it, it will most likely be dropped as they don't want to be ruled against and have their code overturned. If you can get it to trial you will most likely win. If not, you will win on appeal.
That's it in a nutshell.