You can focus on a boss, while healing the party by using the arrow up/down keys. Whatever is highlighted gets the next spell. Unfortunately this doesn't seem to work with the enemy list. One suggestion I have heard on the subject are things such as left/right to toggle through enemy list the same way. I think that would be an interesting idea to implement, though could make regular toggling tricky.

So to my knowledge, no not currently, except for for the party heal/buff exception.

Focus target would be a great feature to add to the ps3, and personally I would want it to replace the auto-lock on L3 which is more trouble than it is worth. (Accidentally hitting auto-lock right as a bomb goes off and you are trying to move out of aoe.... that was embarrassing)