Hello
Hi
I have a few questions regarding pet ferrets
Ask away, perhaps you might want to know which colors they have, or if there's a difference in appearance between male and female ferrets. 
I want to know how their temperament is and how well they do as pets compared to other animals such as dogs
Well, if their name origin will tell you anything, they're little scamps. "Ferret" is derived from the Latin "furittus", meaning "little thief". You shouldn't have any problems with other pets as you mostly keep ferrets in cages.
Are you able to have more than one together or should they be separated.  I would like to purchase some for younger children.  What type of lifespan so they have?
They're friendly creatures so you shouldn't have any issues. Just make sure to do your research on the several distinct ferret health problems that domesticated ferrets have.