Hi Ronald,
I definitely like the ideas you come up with. All across #14, #15, #16, #17and #18, obviously the monkey from the "speak no evil" is a good idea to represent a definition of TACIT. If it was a marketing business, I think its on the right path.
However it is probably an icon that would get me noticed for the wrong reasons in the consulting industry.
Again, I still like the idea of an icon. But its just getting the correct one.
Thanks for your submissions, hope my comments help!