Some daylily sellers "dig on demand", only digging the plant if someone wants to buy it on the spot. They cut back the foliage but leave the scapes, if any. That stops the plant going into transplant shock from inability to effectively transpire and thus the scapes survive. But I'm not sure if you're thinking of potting them before winter or after? I've moved and divided daylilies in spring before they normally flower and they still flowered. If you do it early enough before the leaves have grown much then it's easier, but you can do it later as long as you don't leave the leaves long enough that they wilt. I haven't tried it, but keeping them in pots over winter would be harder on them in theory. When I've had potted daylilies late in the season that I wanted to leave outdoors I've sunk the pots in the ground and they've been fine, that buffers them from the temperatures. The only time I've had them not flower was when I've brought them indoors for the winter, then they often don't flower the following summer - assuming the fan size is sufficient for flowering in the first place.
