1. It's a thick liquid. If you want it to be solid you have to drain it. This takes a day or so.
2. Any container at all will do. I use a milk bottle; I know people who use Tupperware containers, you can use any kind of bottle or jar at all to ferment it in and to store the finished kefir. Or you can drink the finished stuff as soon as it's done every time, and then you don't even need a storage container, just a glass!
3. The milk isn't heated. It's room temperature until you put it in the fridge. You can add fruit, fruit juice, DaVinci syrups, peanut butter, whatever the heck you want to it, whenever the heck you want. You can add ice. You can put it in the blender and make a smoothie with frozen strawberries. Sky's the limit!