Generally in the first week newborns poo does go green at some stage- not all do but most go meconium, brown, green, then mustard. The green usually coincides with the milk changing as you go into lactogenisis 2 ( the milk 'coming in'). You would generally expect it to only be green for a day or two, but I guess its not unheard of to go longer. I'm sure your milk came in quickly though being oyur 3rd baby. Maybe ring the MCHN line and see what they say?

The discharge is normal for I think up to a few months, my baby's breasts were swollen for a few weeks I think. Its called psuedomenstruation if you want to google it. Is it mucousy or straight blood?