Just to provide an update - I have been removing components from the air intake and shroud and cleaning them as I go. Engine bay is dusty (they lived on a dirt road) and I have thus far removed three separate squirrel nests - each was freighted with acorns (under shroud, in air duct and also battery the box).

Two observations - first off I now have significant doubts about how deeply the professional diagnosis went at either garage since most of these parts do not seem to have been removed. Secondly - although the open throttle body is sucking wind pretty hard, the noise has disappeared.

I am not counting it as fixed (yet) - but wanted to express my appreciation again for reminding me to slow down and do some diagnosis before throwing parts at it.