questions about growing in containers (various veggies)

Some of the land at my new place is much more work than it needs to be in terms of preparing it for planting. I was about to lay about some pole beans, various bush beans, tomato transplants, kale...you get the picture. As far as containers, I am about to make a good bit of self watering 5 gallon buckets for my new pepper plants. I plan on using hydro nutes in the reservoir. I'd like some insight on exactly how i should go about the various plants. As far as radish / okra etc go, they seem to do fine in the ground.
 
I should use potting mix, correct?
IS watering from the bottom enough for these seedlings or should I water the top as well?
Should I look into using big tote containers (20 gallon) for things like pole beans? 
 
Thanks and let me know everything yall do! ^.^