so not much that tell them apart
You're right again, only the first one by looking at it wont get evaulated and should say something like $me No such nickname.
You can't make yourself a helper either, they need to add you as a helper, when you "Oper" up or whatever your usermodes will then have a h in it.
I'm not sure about about the <pass> thing, never been on a network that supports half ops. But halfops I would imagine is given identifying to your nickname again you can't make yourself a halfop (%) if you don't have the required priveleges.