Depending on the variety the roots might be super big, might not be. Since they weren't in an optimum location the roots might be growing slow as well as the shrub so you might get lucky. Peonies aren't really hard plants, aren't really fussy, and you can easily dig them now and either replant in a better spot or in a pot--if a pot I'd suggest that you wait until they're out of the ground to decide on a size, they don't like to have their roots crowded like some. If you leave them potted I'd suggest that you leave them at least in part shade the rest of the year, although they're a sun plant the roots don't like to be overheated and they tend that way in pots. You could probably avoid that issue as well by double potting them--plant in a large nursery pot then put that pot in a slightly larger ceramic or clay type pot to act as insulation. As for overwintering it, they can take a freeze in a pot, what will kill them is freezing, thawing, freezing, thawing.....that repeated cycle will cause the roots to rot. You can either sink the nursery pot in the ground overwinter and they'll probably do just fine or put the whole thing in an unheated garage or storage shed, water until the first few inches are damp once a month or so until spring and replant then.

Whenever you're planting them out in the spring when they're waking up they'll need the same consideration you'd give to any other perennial you're moving during it's growth period--extra water and shade for several weeks to let them settle in, will also need more water than typical during the rest of the growing season and summer. This isn't necessary if you plant them out in fall when they're going dormant, also they should be divided in the fall, hence the advice to always plant them in the fall.

Thank you lizbest1 :)

I do have the areas and pots required for potting and overwintering them.

Extra glad you suggested double potting. I do regularly "nursery" plants and bulbs, but rarely use that trick. This year with the border is planting in a ton of irises, lilies, herbs, other bulbs that I already got ready to go. If I can hold over the peonies and baby them this year to spring planting next year that's great. I'm willing to fuss them a bit- I don't like the ants, but they are really pretty and smell nice.

I might be able to get them in in the fall- I assume I would still need to treat them nice in pots through the growing season. But I will be patient and hold out till the end of May or when they start popping to dig them up.

Meant to mention--if you drink coffee (regular, non-sweetened grounds only) spread them lightly around your garden, the ants will LEAVE. I have hundreds of peonies, rarely see ants.

That's used ground, don't sacrifice any new!