>>1897120>First questionAll the documents you mentioned + seaman's book and yellow fever vaccination.
Depending on the flag of the vessel, you may also need flag state seaman's book, medical examination and certificate endorsement. But these matters are handled by the crewing agencies.
>Second questionNo, there are no restrictions for vessel size or sailing area for cadets and ratings. Most of my mates from college did their first contracts on sea- and oceangoing ships.
>Third questionLook for crewing agencies in your country or region, then apply everywhere you can. Searching for your first job sucks, since it's a Catch-22 situation, so you should be more proactive than just filing online applications. But companies do like hiring cheap labour, so cadet vacancies appear regularly.
>Fourth questionLocal regulations are usually not much different from STCW standards.
It is indeed a pain in the ass compared to most other jobs, but once you start in the industry you gradually learn and accumulate the papers and experience that you need, and it doesn't seem so overwhelming.