The flower buds for early Spring develop in late Summer to early Fall so your mac plants probably have them "on" now. They are inside the stems so they are invisible and are located near the ends of the stems. As a result, for early Spring, you do have to worry about the stem dieback.

The flower buds for Summer-ish time from rebloomer macs will not develop until mid to late Spring, approximately. They will develop on new growth/stems that starts growing in Spring 2021. If they get tall and old enough, they will be able to develop flower buds and bloom by Summer time or early Fall. If your macs are not rebloomers (if they only bloom only on old wood) then you do not need to worry about this second flush of flowers.

In zone 6b, I would worry about cold temps as well as frosts. However, down here in Texas, it would be rare to worry about cold temps... although we have had week long bouts of single digit lowss in the past. Most of my issues are due to the plants breaking dormancy due to mild winters and then getting zapped by cold temps in Jan/Feb or due to late frosts. Their dormancy in winter is probably as effective as trying to sleep beside a loud snorer (person or dog). ;o)) Hee, hee, hee. Just kidding.

I have not seen winter 2021 predictions yet in weather.com either... It may be too early (too many hurricanes or tropical systems).

Sigh. Not what I hoped to hear, but I'm glad I asked.

I’m thinking about the same. Even with a mild winter, I got some stem dieback last year, tho I had tons of flowers. I hate the chicken wire and leaves look, and I can see my plants through my sliding doors.

I use mulch inside the chicken wire so, to me, they are mulch storage compartments and the look does not bother me. Hee, hee, hee.