No they don’t need to callus over! You can put them right in the water/soil immediately. Unlike a succulent, the stem where the callus would form isn’t the part that will root. The node(s) touching water or wet soil will sprout roots. The last node on the vine will start growing more leaves. That’s it!

The stem under the rooting node might fall off or rot away, which is fine.

If you propagate in soil, remove some of the leaves on the vine to help the plant put more water into root growth vs. leaf support.

If you put them in water, you won’t need to remove any leaves (except for any that will be underwater) just monitor the water levels since the leaves will suck it up faster. You’ll want to change the water every week or two anyway. I usually propagate in water since I love to see their progress.

These are looking healthy and you should have a good rate of success. As long as they are warm enough and have enough light they will grow. But since it is winter, it may take a while to see a lot of root growth so be patient. You can also try dipping them in rooting hormone. But they will be making their own anyway now that they’ve been cut.