Oh, notice that although Ivan has little in the way of guns, he packs a hell of a lot of explosives and other throwables - those are ranged weapons too, and powerful at that. And when he runs out, he has a large stash onboard to replenish. So it ain't that bad, even if he lacks really long-range capability. Even flamers and scatterguns will be way more useful here than in a normal mission. The only resource he needs to carefully guard are living soldiers
My only complains would be that he:
- didn't upgrade from Pirate to Metal yet - really, there IS a difference;
- didn't take that couple of Tech Blades that were produced in the meantime;
- and, most importantly, what's the point of taking mortar if you only take 3 rounds? It will help, no doubt, but 10 would be more like it
Anyway, this mission is going to be so climatic. A pirate gal shooting crossbow at a green sea monster, how cool is that
A (stupid) advice: Avoid/Kill guys that shoot stuff at you, especially celatids
Getting hit by a Celatid is usually an instakill. Oh and save your time, Celatids ARE immune to Acid, Lobstermen ARE nigh-immune to AP, HE, Laser...
Another pointer - if a guy attacked by Incendiary is set on fire, it means he DOES take some damage from fire. Immunes cannot be ever set on fire.
EDIT: Regarding the tech: Boarding gun is a good research bet, it leads to important advancements in firearms area (even if some won't be immediately evident).