Dex & wisdom would be the important stats for sailors IMO (i am not saying strength and con are useless, but just not as important, they would be 3rd and 4th IMO).
Darkvision wouldn’t do a damn thing, its range would barely get off the side of the boat.
Poison resistance is not disease resistance.
Some spoiled food would be poison, but some would also be disease (depends on how it spoiled and the food).
In order for short stature to be relevant to ship design, they would need a completely custom designed ship tailor made for them, which would have benifits but sounds unlikely for what pirates would be sailing. (That being said, a dwarven merchant ship designed speciifcally for their stature would be a massive pain for normal height characters to battle on)
lower speed means they swim slower too which means going overboard is even worse.
EDIT:
dwarven submarines!
short stature actually hugely relevant as submarines are notoriously cramped
darkvision means no need for lights in the sub, beneficial for multiple (admittedly somewhat minor) reasons.
honestly no clue what stats would be important for a sub, no argument here
toxic gasses less of a problem thanks to poison resistance
Dont even need to go to the surface, a fully underwater submarine port could be connected to existing dwarven settlements near the ocean with the correct design and planning.
I have issue with almost all of your points.
EDIT: dwarven submarines!
Dex is valuable for tall ships, but steamships and ironclads, str/con is the way to go.
Dex would be super important for them too. Cannons of all flavors aim with dex due to being ranged weapons.
For sure wisdom being the highest priority unless they always sail near the coast, but to be fair you only need 2 people with high wisdom