I am wondering if anyone might have a guess on when the crappie might move into shallower water due to the mild winter?

not as mild as last year, and not as wet either, at least in n texas. the fish won't have to worry about all that flooded brush like last year. mud banks only. maybe the shallow brush piles will come into play.

how long do you tnhink till they move up though?

they normally won't spawn till water reached 65 degrees but, they can move up to prespawn postion a week prior to spawning and sometime move in and out as the water temp varies but, I ain't no expert, just my observation

When the water temps get in the sixties. But I have caught a few in the high 50's.

56-57 degree nighttime surface temps. Not time yet