Older stems are stronger than new ones. But I would do nothing until they are more fully leafed out. There are many with portions that have leaves and portions with no leaves. So I am not sure what will happen with those or how will they end up looking (ok, ugly?). You may have to see how they look later and see if you choose to prune those too or not.

its getting late for pruning so I would just wait and see what happens. In a month you'll have a clear idea of what wood is leafing out and what wood is dead. At that point if you want you can remove the dead wood so the plant looks neater.

I usually prune mine to 12-18" in early spring. Once they fill in -- no "dead" wood is seen.