For the future, you should pick up a stealth skill, it would come in handy, I think...
Here's the formation I propose.
Like this
See, here's the catch — Nebka has a very unusual line-of-fire range, so ranged units can stand further back. Henry should tank for a round (and maybe try to use Needle Shield IV before the fight starts? Worth a shot). Zeykin makes a dash? Joe — immobilizes?
Here's how the line of fire works, by the way (the entire perimeter of the square is covered by the harpoon with a range of 8):
Like so
