Can you ice the layers (for in between the cake) while it's still frozen or still early in the thawing process?
I've always waited until the cake is fully thawed. I worry that icing a partially frozen cake would create liquid buildup between the cake and icing which could lead to soggy cake or slippage in the frosting.
I just did one this weekend that was partially frozen (center only). I had left it out to thaw for about 20-30 min then leveled and crumb coated. No rpoblems.