You should probably solve the issue of "how will it start" before you start "installing engine".
Because else maybe you will have to uninstall it again.
Anyway, for EDC15C6 this should work and probably cheapest solution:
https://shop.carlabimmo.com/en_US/p/Julie-MERCEDES-IMMO-OFF-Emulator/157Recommend to solder it properly, so it does not fall off in the middle of the sea.
But also just the immo is not the only thing, you also need to convert the pedal to the hand throttle, and a lot of stuff will need to be deleted/modified.
Why not just use a marine engine in the first place?
