get your tank stable for months before adding coral or any desireable fish especially a dragonette , start off small where you dont have alot of live rock go slow, you wont need a filter(canister) but a skimmer wouldnt go a stray and go with a sump/refuge if you can the benefits far exceed not having one. the white stuff is to be expected and will dissappear in time its a sign your cycle is not finished , pretty sure its just dieoff was your rock cured when you bought it or sold as un-cured?? you wont need lights if your just cycling without any fish . get your system established , once your readings are good wait a few weeks and see if they stay good then you should add a clean up crew like some snails and shrimp etc. once theyve been cleaning for a week or two then think about what you would like to keep and if its size will be a problem later on because they get big fast, also if you plan on keeping corals remember that alot of fish and other tank critters arent reef safe. the list is endless my friend read read read ask ask ask , if you dont like spending money and watching it die in a few days id do everything slow untill your absolutely sure you understand it and even then youll find its taking the plunge and forcing the knowlege upon yourself that keeps you going
cheers and welcome to one of the most rewarding hobbys out there im looking forward to seeing how your tank set up. keep us posted if you have any questions post them here and im sure someone will answer to the best of their knowlege