From something I heard long ago when I spent some years on the Oregon coast. I had read a novel called "TRASK" which went into many of these concepts.--I no longer have it, but it was a good exciting read.---This is what I recall about the nomenclature:

Tamanowis = medicine--as in good medicine or bad. (And for all the medicine the medicine men have made, STILL "the evil ones remain!") This wasn't doing magic in any Harry Potter or Gandalph sense.

potlatch: was several things, but mostly it was a ritual divesting one's self of possessions and giving it all away with a free good will. That would seem crazy to the capitalists that the white people were. So, it was made illegal.

mowitch---is akin to luck with -- a touch of 'good medicine' tossed in. (It can't hurt!)

That's my two cents.

Art Thieme