They aren't too picky about soil--Supersoil, Miracle Grow, etc., are all generally fine, or you could make your own, or spend a lot on soils like those from Fox Farms. You can always add ferts to lesser quality soil but you tend to get what you pay for.
As for planting, you can put both rhizomes in one pot but chances are that both will take, so unless you are using really big pots (22-24"+) separate pots might be a better option. Then again, if you plan to transplant next year in soil, it doesn't really matter too much. Still, get the biggest pots you can afford/have space for because that seems to be the major factor when container growing.
Bottom line is that they are pretty easy to grow and there's a lot of different ways to do things without one way necessarily being the best. Jump in and have some fun with it--you'll learn along the way.