The LOD file(files) for the helicopter should be in its actual folder - which should now be in /aircraft/seaking.
check the seaking.ini to see if the lod names are the same as the files and the same case.
You dont need all the folders - just create the ones you need
read section 1 here
http://combatace.com/topic/44026-converting-older-planes-to-work-in-sf2-a-basic-guide-by-migbuster/
Also on the link you will see how cockpits are added (22).
See sections 15 and 19 for other issues you mentioned
For sounds you need the actual sound file in the sounds mod folder, and a proper reference to it from the aircrafts _data.ini
For pilots a breakdown is here:
http://combatace.com/topic/44033-putting-pilots-and-ejection-seats-in-sf2-by-migbuster/
play around with it and see how you get on