Hey I didn't carefully read the previous posts but I skimmed for any mention of OTC and didn't find any. I've had a lot of experiece with localbitcoins.com, an over-the-counter (OTC) service, and highly recommend it for both buying and selling anonymously. 

Localbitcoins has no identifying information. The email can be fake. The btc address you'll use is on their site, so wherever you send the coins could be anonymous (laundered). The phone number you can optionally provide can be a burner. It's the ultimate, imo.

When you meet up, most transactions go super quick in a public area. They can also be conducted in private, really, wherever the fuck you want. Essentially, no personal information needs to be given up when you buy bitcoins with cash.

There have been some explorative papers on OTCs importance to the validity of btc but I don't currently have the links. Check out this interview with nanotube, however, who talks a bit about one of the first OTC listings, the channel #bitcoin-otc:
https://www.privateinternetaccess.com/blog/2012/03/interview-with-nanotube-founder-of-the-bitcoin-otc-ircs-marketplace-on-bitcoin-multisigs-and-security/


DISCLAIMER: I'm solo, no affiliation with any of the companies I talked about. Enthusiast like yourself.