1) The engine is going to be run in the salt-sea side water (Adriatic
Sea on the Croatian coast). Is there any special instructions for
sea-water versus the lake-water?
2) Since I will be the first using the engine, unpacking it from the
crane where it was shipped from the US (family just bought it in the US
and shipped it to Croatia)

3) Cranking it before putting it onto the boat - you mean outside the
house, without water, cranking it and running it for a while?

With our old engine, which was bought before I was born, what we used
to do every summer is this. After every summer we would give it to a
local mechanic who would lubricate it and put some sort of preservation
oil. Before taking it to boat, we would take it outside, take out the
spark plug, crank it blank for a few times to get the extra oil out.
Then put the spark plug, turn the engine on, run it blank (with little
fuel) in the air until the engine conbusted the extra lubrication thing
and oil (produce lots of exhaust). We would remove the fuel line, the
engine would idle (it had no idle/neutral, just low speed) If if
cranked, it was all good, if it did not, then to the mechanic.

However, this was an old 2-stroke engine, with no fuel-injection (you
had to mix the fuel with right kind of oil, for every x liters of oil,
we put x liters of fuel into the engine).

Thank you for the info,
George