AFAIK, go down fighting bonus is applied when activated, not during his duration. That mean if you activate it while at 10% hull, you'll receive the according bonus for the whole duration, no matter your HP after activating the skill.
So, your alpha strike will not be ruined by a heal, except if you receive the heal right before using GDF, but a new animation wouldn't help in this case.
Well, when you select that player, you see all the buffs and debuffs on him or her in the tray that shows along with the hitpoint information. Sure, being able to see it on the screen without having to select the target might speed things up a little, but the info you seek is already available.