Animals will generated in game items like milk, wool. Which will provide more in game coins and score over time.
Pick the avatar you like to play with, avatars do not have any profitable traits and are purely cosmetic.
Buildings can provide traits for your farm, this can be extra storage to hold more items before selling, a mill to turn Wheat into Flour, etc.
Decorations give no traits, these are just cosmetic to make your farm look better or unique.
There will be different type of plots, but the plots will be limited! Owning a lot of plots can put you higher in the ranking as you can add more crops on your farm. Some plots also can have beneficial traits like less watering or fertilizing need, faster crop growth and more.
Worlds are purely cosmetics, everyone will have the default world for their farm. But if you want your farm to be on Mars and show-off your awesome farm to the community, you can change the layout of your world by holding one of these.