Nice finds. That's kind of an unusual batch of coins coming out of a little stream in a fairly small space. The kid theory is a good one but if it were me I think I'd take a really good look at the stream itself. Just a hunch but after run off has finished this year, go in with a gold pan and sample up and down the creek a bit.
Chinese miners worked the coastal areas from California all the way into Canada. They did very well going after the fine flour gold that the European miners didn't want to mess with. An odd collection like that could have been carried by them as they
had come into contact with so many different people. It only clicked because I've found similar collections around some of the old Chinese camps. Just a thought.
Deepsix