First off Welcome to BYC!!! Secondly, she seems to be broody, as these are all signs. The poop is from lack of food, and the puffing is protectiveness. Keep feeding her and watering her, and just let her chill, this will pass. Just sit back and enjoy the show! :pop
There are many coop threads on site, posted by many users. There are also ones on Pintrest. A good coop by a member is built by @Pyxis, check it out. It all really depends on the style you want and the amount of birds your getting. :bun Good luck and welcome to BYC! :bun
They are a bit too young to tell, especially with barreds, as they both can have combs, you will, for now, have to go off of temperament. Good luck! :D :D
Welcome to BYC! I am glad this site could help you. Hope you find answers to any questions you have! I recommend finding your state forum: https://www.backyardchickens.com/f/26/where-am-i-where-are-you
:bun Welcome to BYC! It is great to have yet another member here. This site is the largest source of chicken math plagued people in the world. Enjoy your time here! :bun