with all that magic your main problem will be the prices. in elfheim you'll need to train for quite a while to get enough money for the good spells. seems as DoS is easy, as long as you stay at a reasonable level, you will be fine. you'll have tons of healing magic so the only problem will be making sure you have enough MP and ethers. SoC wont be hard as long as your on a good level. seems as anyone can equip the "ultima weapon" things should be fine. with the right healing and buffing spells omega and shinryu wont be so tough.