Roots are starting to pop out the bottom of all th...

I'd wait until your roots are a lit bit longer so you can adjust the height of your water in your bucket system.

Yes you can transplant but you don't need nutes just yet. Maybe cal-mag + humic acid to boost the growth...

Hi @LuckyMfer! Yes you can transplant them into their final DWC container. They will appreciate nutrients if and only if the EC is low, so take it easy when adding fertilizer, do it step by step and adjust your feeding schedule to your plant's health and reactions. Also, I recommend to proceed to seedling selection: by casting the strongest seedlings and killing the weakest at early age, you will ensure yourself a nice grow with only good phenotypes, I guess you don't like to grow weak plants - me neither - seedling selection really improved my results. Hope this will help, keep us updated and happy growing!