I have been looking into moving counterfeit USD for a while and have researched a variety of vendors. I am looking for general opinions on the topic and whether it is worth it. And i would like to do vendor verification, but do not know the protocol surrounding it. Any Input is greatly appreciated!
Any "vendor" that isn't on an established market is a scam. All of the ones from the hidden wiki and /r/onions are just easy ways to make money from the greedy and stupid. Also counterfeit isn't worth the risk. It is really the only thing you can fuck with that is 100% guaranteed to bring police (and secret service) attention to you. The precautions you need to take to be reasonably safe using it (only carrying one fake at a time, only small purchases, constantly moving around to stay ahead of news and bank alerts) means you have to work very hard with lots of risk to make any real amount of money. That is unless you want to do something phenomenally risky like trying to do a drug deal with it.
Edit: looking at some of the sites you think are legitimate from your post history
Seems totally legit bro.