Hello

and Welcome To BYC! One thing with getting older older chicks is you have a better chance of being sure they are hens (always a question at a feed store), won't have to do much so far as a brooder set up since by six weeks they usually don't need heat unless it is unusually cold, and you will get eggs a month or so sooner. If you get them tiny, they do tame easier, but even older chicks will tame quite nicely if you work at it, most chickens are pretty food motivated.
WIth a rooster, unless you want to hatch chicks, you really don't need one, if you don't want to hatch chicks you will probably be better off to get another hen for the extra eggs. As for breeds, do you know what your feed store has and if they have straight run or sexed pullets? Your best layers are usually the Red Sex Links like Golden Buffs or Red Stars (and since they are sexable by color you can be sure you are getting girls) and White Leghorns, most feeds stores carry both those. If you want a rooster you will probably have to get straight run chicks (as hatched so should have about 50/50 males/females).
Be sure to check out the Coops section for ideas on coops
www.backyardchickens.com/atype/2/Coop_Designs and X2 on the Pallet Coop idea, they can be any size and as plain for fancy as you want... there are lots of threads on them if you do a search, ie
https://www.backyardchickens.com/t/550804/pallet-chicken-coop-ideas
You might like to check out the BYC Learning Center, lots of good articles on all aspects of chicken keeping.
https://www.backyardchickens.com/atype/1/Learning_Center And it is always fun to check out your state thread for chicken keeping neighbors, they may also have suggestions where you can get coop supplies
https://www.backyardchickens.com/t/270925/find-your-states-thread