Is Zakah due on the orphan`s money?
Yes, Zakah is due on the money of the orphan.
What is the ruling on public street water if it gets on a person's clothes or body?
The default ruling is that public street water is pure (tahir). If one is certain of its impurity (najasa), then a small amount that gets on the lower part of a person's clothes or body is overlooked (excused). And Allah the Almighty knows best.
What is the ruling on discharges two or three days before the expected period of menstruation and the light-colored blood accompanying it? Must the woman abstain from prayer during this period?
If the total duration of these blood-tinged discharges reaches a day and a night (24 hours) or more, it is considered menstruation. If their total does not exceed 24 hours, it is not considered menstruation but is irregular bleeding (dam al-fasad). Each woman has specific cases for which she should ask the scholars. And Allah the Almighty knows best.
What is the ruling on the ablution of one from whom blood exits from his nose or a wound?
Blood flowing from a wound or a nosebleed does not invalidate ablution. However, performing ablution is recommended to avoid scholarly disagreement with those who make ablution obligatory after blood flows. And Allah the Almighty knows best.