I have a few small brugs potted and inside plus several cuttings potted to root. My Alocasia is pulled out of the outside oil, dirt shok off, most leaves cut off, and plopped in a smaller pot just the balled up root mass. My cannas are dug and stored inside. Of the 3, only canna would I feel I could have some surviving mulched. And I am zone 7b.
Oh gee, just realized I have thought zero about digging a crinum just to be safe. One has lived for 3 winters in my warm bed, so probably all ok.