Welcome to our flock!
Glad you could join BYC! Some good breeds for egg production that also have good temperaments are Black Sex-Links, Red Sex-Links, Australorps, Orpingtons, Wyandottes, Easter Eggers, and Sussex. All of those have reputations for being gentle and docile around children, especially if handled often as chicks.If egg production isn't a huge priority, you could get Cochins or Silkies. Those are very kid-friendly, too.
I've never bought a coop (only constructed ones), so I can't answer your next question. I do know that most pre-made coops that are sold are too small and overestimate the number of chickens that can fit in them. Keep in mind that each chicken usually needs 4 square feet of inside space and 10 square feet of run space. I suggest posting in the Coops section for some good answers as to where to get a coop:
Coop & Run - Design, Construction, & Maintenance If you do decide to build, be sure to check out this section for lots of nice coop designs:
Chicken Coop Plans
I also suggest taking a look at the Learning Center:
Learning Center Articles It has lots of articles and information on all aspects of raising and keeping chickens.
If you can't find answers to questions, just ask! We'll be happy to help out in any way we can.
Good luck with your future flock of chickens.