Samoa is on the right side of the International Date Line in the Western Hemisphere.
Travelling west the international date line is further west. The answer is no
The international date line runs between them.
Although the line at 180° passes right through Fiji, the International Date Line at that latitude is relocated to the east sides of Western Samoa and Tonga. I don't know how many miles that is, but it's at least 6° of longitude east of 180°. (Western Samoa relocated the International Date Line to its east side in December, 2011, less than seven months before the time of this writing.)
Probably American Samoa. It's immediately east of the International Date Line.
The countries with the longest time difference are those that are on opposite sides of the International Date Line. For example, Samoa and American Samoa are 25 hours apart due to the time zone difference at the International Date Line. Other countries with significant time differences include Russia and Alaska.
The islands of Fiji are on both sides the Anti-meridian (-180 and +180 longitude) but the International Date Line (IDL) is bent to give uniform time (UTC+12) to all of the Fiji group. This makes Fiji a very interesting region to map makers.
No, the international date line is a line of longitude, not latitude.
Both. The International Date Line is nominally the line of 180 degrees longitude, both east and west ... exactly opposite the Prime Meridian and half-the-earth away from it. The Line was drawn with some jogs and zig-zags in it for political reasons, mainly to avoid having it split island nations or contiguous areas of national interest.
they are all located in the east and west side of the southern hemisphere divided by the international date line
They decided to move their calendar to correspond to the other side of the international date line - because they have more trade with them (specifically New Zealand).
no countries lies in international date line