I've seen Preston's original photos of the Whitehorse Engine House fire and it's clear that one of the ET&WNC engines was hardly damaged. WP&Y No. 51 'survived' OK and is now on display in Whitehorse and there's no evidence of fire damage. I think it was more of a case that the Alcan construction was winding down by the end of 44 and they had plenty of motive power at that time so there was no reason to restore 10 or 14. They just went onto the scrap line in Skagway with the others and when it came time to ship them all South to Auburn for scrapping, off they went.
There is no doubt that many of the engines sent for scrapping after the war could have been rebuilt, a number of the K-28s for sure, however there was very little interest in narrow gauge steam at that time. The D&RGW was given the best one # 472, but they had their 'noses out of joint' and refused it. The 'wisdom' of the time considered diesels the wave of the future and steam as obsolete. A lot of really ueseful stuff got trashed after the war just because of the attitude of the day.