Just because it is in your contract doesn't make it legal!

Realistically it could be worth checking your local laws regarding it and potentially speaking to a lawyer as some will do a free consult to see if you have a case

More or less yes you did American English correctly. More often I just refer to them as semis without adding the truck part, some also call them tractor trailers. It was clear what you meant though so only need to change it slightly if you are going for full American English

This list is quite disingenuous and requires a whole lot of caveats to be even technically true.

Let's take Liberia for example. European powers had trading posts established and the country was later colonized by the US. So only in the strictest reading of definitions of being colonized by a European power would it be on this list.