One way to handle it (the latter half, at least) is to abuse snipers starting with squadsight. I dealt with that mission by turtling on the upper section of that boardwalk/balcony so that the pods had to charge across the docks to get to me. I managed it without rockets, but the only reason one of my troops didn't get a chest full of alien wing-wang was because for some reason it decided to acid him instead. After that, I posted my pair of snipers on the roof of the boat at the bottom-left corner with an infantry for security, ran my assault up along the roundabout route to the upper deck, and had the remaining three popping the new spawns as they appeared.
Once they started overflowing, I had the snipers take down the spawns that went after the assault, and had the rest of the squad book it for the 'ranger.
Basically here's your ideal squad, at least by my reckoning: 2x sniper, 1x rocketeer, 1x scout (with the light armor and SMG to do the suicide-run), 2x assault, 1x infantry. The rocketeer puts both pods into killing range for the rest, and then you have them to guard the snipers while the heavy guns go up to camp the whale. The scout is speedy Gonzales and the snipers can pick off any unfortunately positioned Chryssies.
But the real tl;dr is FUCK THAT MISSION SO HARD/]ashfejasfn