You can move the lilies but they may be stunted this year by doing so- the best time to move and divide them is late October before the ground freezes.
I always plant out my Dahlias in about mid April- (do not water them till they come up). You could probably move them as is to a cool spot in the greenhouse and not do anything with them- planting them directly outside in a week or two.

Are you saying you plant your Dahlias in the ground mid-April? I am about 350 miles NW of Mpls, so that still might be a bit early for me. Which is why I thought the unheated greenhouse in pots would be ok to start them. Then I can put them out when the ground warms up a bit more. I am going out of town on business from April 13th to the 26th. Then again from May 2nd to May 13th. So I am trying to get some of this ready before I have to leave.

Thanks