Personally as Morcar I'd never allow a weapon swap. Seems too much of monkey business to me. Potions are ok, but whole spears and stuff is too much for me.
We shouldn't even count on that, don't send Orthos round with a swift wind. We'll get the giant where he stands, now it came down to this.
The only thing I'm afraid is for any traps in my way to reach the giant.
Here's how it's gonna go down.
gernaldo attacks and moves 3 N.
orthos attacks diagonally and stays still.
magnus mind locks the giant (there is no way it's not gonna mindlock him for at least one turn so we are good - my guess is 3 turns easily).
jason moves South but does not overpass magnus/gernaldo even if he can reach (to protect them from the goblin arrow).
ibagaza moves closer to the giant, falling into any trap in the way.
the goblin archer runs to the corner and attacks jason.
giant 1st turn mindlocked.
then we all play, orthos and ibagaza attack normally with 2 dice, magnus casts courage on jason so he moves and attacks with 4 dice,
while gernaldo moves to finish off the goblin.
giant 2nd turn mindlocked.
then again we attack, 2 dice from orthos and ibagaza, 4 from jason, 5 from magnus' genie, and gernaldo moves back south.
giant 3rd turn mindlocked.
we attack again, but if the mind lock ends, magnus will cast tempest while the rest of us make three 2 dice attacks and one 4 dice.
In the tempested round he probably will be dead already or have 2 body left, so we take our chances that the 4 attacks and a ball of flame will take him out.
Anyway, ibagaza moves:
tasoe rolled 2 6-sided dice:

Full East and then full North as far as I can.