For December 28, 29, 30 there is some clarification in Ernie's copy of the Chama engine dispatch book (this covers engine departures only, not arrivals).
On December 28 the book shows 487 and 493 called for 8 am heading east. As you surmised, it is pretty certain that 493 was turned in Antonito to help extra 498 west. I am surmising that 498 and 493 didn't get into Chama until very late on December 28 or early on December 29.
The book shows no departing engines on December 29. So the crews had a full layover day on December 29 and no problem with hours of rest.
On December 30, 493 and 488 were indeed called at 3:00 am to run east. 493 derailed at Windy Point and 488 returned to Chama. On the same day 498 and 484 were called at 7:30 am to run to Durango. 498 and 484 returned to Chama ( if they had actually left Chama). At 12:01 pm 484 and 488 were called to run as Work Extra to Windy Point. They re-railed 493 and 484, 488, and 493 then returned to Chama.
On December 31 488 and 484 made a flanger run to Alamosa. 493 and 498 ran to Durango.