A bit confusing task, but I can do it. Not clear which parts already written, which not written. As I understood, Indicators already exist, need: Volatility determination indicator, Entry indicator (wth 4xVolume break and Nbars above). And scanner. to scan stocks for vol break. A think you understood expert can trade only on attached symbol. Scanner can show you symbols with entry conditions, but expert can't scan, and will trade only one currency. In MT4 possible to make multicurrency expert. TS don't have such ability.
Time depand of how good I will understand it. I will ask questions about Expert rules. Simple traiding strategy I can write in 1 day, Multitargets for TakeProfit may take 1-2 days. Scanner simple, 1 hour, if entry rules already will be written.