For me....
I'd use a 5-gallon bucket w/drainage holes....5-1-1 or, "Modified 5-1-1-1" quick-draining mix, and I would shy away from those mixes that are loaded with fine peat moss. Water should pour right through a good mix and not turn it into a swampy soup. Given the correct culture, a fig tree can grow very quickly, and the roots will fill smaller containers, making it necessary to keep doing up-potting, often.
For the stem with the bend: Use a tall and stiff, bamboo stake, and tie the stem first at both the top and middle, and then start tying the stem at the top drawing it closer to the bamboo stake. Do this by small degrees if necessary. That bent stem will straighten out over time. Use some foamy padding to protect the bark if its gonna get rubbed by the stake. Keep tying the new growth to the stake as it elongates. You'll have a straight tree in no time at all.
Frank