Anima is quite easy to get actually. You just pick up the treasure as you go through the trials and youll get it. You'll have to go back to zanarkand and do the trial once more. You get the bevelle treasure automatically, so you dont have to worry about that. I suggest you train Wakka, Rikku and Tidus Up a bit before you go to Baaj and make sure they have Ribbon or Stone-Proof. Try to learn some magic if you already havent. Geosagneo (sorry for the spellin') is very weak against magic so it helps alot. Also, when he inhales a character, if you get a trigger option to fight back, it might help to defend instead. It can be a pain in the ass if you arent ready.