I would start over. No point in cloning a dead/dying plant. Your plant looks very dry, as if it was underwatered or became severly root bound. If there was also powdery mold, clean your room down good and get better ventilation before restarting.
Plus whatever killed that plant may spread. I'd get rid of it and thoroughly disinfect the pot.
Powdery mildew (you mentioned white stuff) is usually a sign things are too damp. So I would wonder how healthy the roots are with a plant that crashed and burned like that