I believe the only reference to "Eachus" as a German name came from the Cope/Ashmead work, "Genealogical and Personal Memoirs of Chester and Delaware County", 1904. I'm sure these two men were good genealogists but it seems that they did their research once and then replicated their work through a number of local histories and published family genealogies.
From Cope/Ashmead in a short bio on George W. Eachus (b. Jul 23,1871)..
"George W. Eachus, an enterprising farmer of Chester County, is descended from a family of German origin which has been resident in the County for two hundred years."
I have seen this error replicated thru many different genealogy websites on the net. I searched on-line white pages for Germany and found no Eachus surnames there. It would be very unlikely for Robert Eachus to have been of German ancestry. He settled among many English and Welsh Quakers in Chester County.
Do you know of any Eachus' who claim German Ancenstry???