Not as long as it is in plain view and is not disguised as something else.
Is it legal in state of CA.
yes.
yes
Yes, stun guns are legal to carry in Texas, unless the stun gun is in the shape of an item that is already deemed illegal to carry, such as a baton, sap, or brass knuckles.
If you're referring to an expandable baton, they are legal, generally speaking, but some states in the U.S. require you to take a training class in order to carry one. I'd guess that some states don't allow you to carry a baton, so the answer is, it depends on where you are. For reference, Asp is a brand name.
Anything that is legal in the civilian world.
In the US
Depends on the laws of your state. In Virginia, open carry is legal- with or without a permit. In other states, a weapon may not be visible. You did not say what place.
It is legal to carry a key chain.
This will vary from state to state / country to country but for the most part Kubotan is legal and entirely unregulated. Some places such as airports / courts / police stations etc may give you some trouble or ask to leave it outside or hold it until your finished and leave.
The legal BAC (blood alcohol content) limit in Virginia is .08%
It is legal for a citizen to carry Mace pepper spray in Pennsylvania.