The photos are kind of tiny but from all things considered, it does indeed look like a hydrangea (probably a paniculata of some sort). You could winter them in the pot for this winter and evaluate the size next year on whether to move them up to a bigger pot or plant in the ground. I see you are in zone 8 so they should be okay to let them be. I let some cuttings out this past winter in very small pots (on the ground) and they came through just fine despite the extra cold days we had.

You could plant those end of this month, or leave them in the pots and plant in Spring....either should be fine in Z8 although the roots will be a little more protected in the ground. 'Bring them through winter'....you didn't mean bring them inside, did you? You don't want these indoors, let them experience winter dormancy.

Limelight and Little Lime bloom like you described. The more sun the blooms get, the faster they turn white. So if you like them to stay green, pick a spot with 2 hours/less or with bright shade. H. arborescens Annabelle also starts green and turns white but your blooms and leaves do not resemble Annabelle's. Of course, when the plants are very small, the blooms may not look "right" for a few years.