Creeping phlox can go in the ground now if your ground isn't frozen, ss. So can the sedum. Those can definitely be planted closer than 18 inches apart, if you want, but both will fill in fairly quickly once they establish, especially the creeping phlox. Or wait until after last frost date to just pull or cut some pieces of those two and stick them in the ground. They are usually easy rooters. Creeping phlox especially is very easy to root. Most of the sedums are as well. I believe the Sweet Woodruff would do likewise although I've never done it like that.
I have a lot of those plants except for the geraniums which I'm just now getting established. I have a feeling it would be okay to plant early as well.
This was taken in March (second year). We're the same zone.
