>"if the FBI or other 3 letter agencies want to find out all your financial activity they'll probably be able to no matter the source of money you're using."

Then why are you trying to attain privacy at all if you believe this?
Unnannounced channesl ironically gives up plausible deniability and doesn't offer you privacy from your counter party
Ecash anonset is fractured between mints and is custodial, so you introduce the ability to get rugged, fractionally reserved, or shotgun KYC'd
Everything else you listed like Silent Payments only solve part of the problem (receiver privacy - and is less effective without the others). It's a mishmash with no comprehensive solution.