If your rockwool has a place for you to stick a stem or seed into, then this may be possible to do. I would take them gently out of the soil, wash the roots off, and then place them in the rockwool. Make sure to soak your rockwool in water for 12 hours-24 hours. Then place the clone and or roots into the rockwool. I would not recommend starting them with nutes in the bubbleponics system. Idk if I would do this with all of your clones, try it out with 1 or 2 clones first (depending on how many you have). If there are not any roots on 1 of the clones you are going to use, scrape the bottom and sides of the stem which is going to be placed into the rockwool gently, then dip it in some water and then some cloning solution if you have some. Do you know about proper lighting for vegging?