if i killed the lakelurks and moved their corpses somewhere else (by the harpoon on the docks for example) would they spawn there instead of the platform?

if not, is there a way to stop them spawning?

i am on xbox and this looks like a cool home

No, they will still spawn.

curses

Could just leave a companion there.

They will spawn wherever you dragged them to, but there is a routine in all critter/NPC AIs that compels them to head back to their 'home base' if taken from it, so they will eventually spawn back there even if you drag them all the way to Mojave Outpost and dump them behind the fence.

There is a 'fix' of sorts for this if you are on a PC:

1. Open the command console by pressing the ~ key
2. While in the console, click on the Lakelurk's corpse
3. Type in 'disable' (without the ' marks) and hit 'enter'; this will remove the corpse from play
4. Close the console by pressing ~ again

Any corpse so removed ceases to exist as far as the game is concerned, and the respawn routine will ignore all calls for that actor's RefID.