Shortcuts For Country Names

Yo, can anyone please tell me possible abbreviations for these countries' names? I am trying to go sub 5 on the Countries of the World quiz, I am currently at 5:07, but I would like to push even further. The countries I care the most about are:

Marshall Islands;

Solomon Islands;

Burkina Faso;

Sierra Leone;

Guinea-bissau;

Equatorial Guinea;

Lesser Antilles countries;

South and North Korea;

Ivory Coast;

Saudi Arabia;

Netherlands.

If you have any other suggestions please feel free to share. Thanks in advance