The hawkfish should be a large specimen. I've had a dawrf lion attempt to eat a hawkfish before, he wasn't successful, but it was close and you should've seen the hawkfish's reaction.
So just make sure you get a larger specimen, and that combo should be fine.
As far as the puffer goes, I never kept puffers with any of my dwarf lions, so i'm gonna leave that for someone who has kept the two, or attempted to.