in WP&YR service Sept '42

The way I am reading the chronology is they were shipped out of North Carolina end of May, arrived in July, were shopped until October and then put in service.
Rick
They were in service in Skagway in September according the the Engine House Register. Unfortunately the EHR for the period prior to Sept 23, 1942 is missing so we don't know for sure when they went into service. Moore does not mention them from his August visit, but then he didn't spend time at the shops and got the roster he published from Richard A. Horn.
However they didn't get the smoke boxes insulated, the fluted caps removed, and the cabs moved back until the following Summer when they were refitted at Tacoma WA. After that, 10 still has a W.P.&Y.R. lettered tender.
There is a bit of confusion regarding "shopping" and "winterizing" and what happened when, as evidenced in your quote from Johnny's book. He's probably discovered a lot more information since the book was published.
Mike