New growth is a good sign.
As long as they are not drooping or severely wilting they will probably pull through. Yellowing leaves is normal, they are going to consume their reserves as they try to build roots, the new growth shows they are still alive and building towards new roots as well.
Giving them a very mild nutrient, especially one designed for clones and seedling could help with the yellowing, and these often have ingredients in them like rooting hormones, and other things, to help stimulate rooting as well. In this case, a light foliar spray could help as well. Very mild, we are talking 0.2 EC or less, like 100 ppm or less.
“Clones, young plants, seedlings, and every marijuana plant in vegetative state will experience extreme benefits with foliar feeding. Because clones aren’t rooted, they require foliar feeding as a means to develop roots and avoid yellow discoloration (a frequent problem for cloners).” ~Robert