Welcome to both the forum and the hobby
5-10 gallon tank will be enough for no more than two emperors. I'd recommend getting a pair to observe the communal behaviour as its far more interesting than when they're on their own.
If you get a pair, it will have to be either two females, or a male and a female (the male you would ave to separate from her if the female were to get gravid) {pregnant}.
There are many species of scorpion in Africa, but the scientific name for emperors is
Pandinus Imperator.
Don't keep them by the window. They are negatively phototactic meaning they don't like light of any sort. As long as they are kept in a room where the room looks brighter when the curtains are open or whatever, then they will be fine - But keep them out of direct sunlight.
He can only say that they are about two months old if he has bred them himself.
Crickets, locust and roaches are the most common feeders. I like to stick with crickets and the occasional locust.
Just small crickets will be fine for them to eat.
As for the environment, I'll leave for someone else to answer as I'm running a bit short on time.
