All four sentences are correct, in my opinion.

They are all correct. The only difference is in emphasis. In the mountain example, the part between the commas is called an appositive. An appositive is usually used to supply a further piece of information in addition to the main piece of information. The sentences put the emphasis on the main piece of information (i.e., the emphasis is on the NAME of the mountain in the first sentence, but on the fact that the mountain is the HIGHEST in the second). Similarly, although the Scotland example does not uses an appositive phrase, the sentences emphasize that fact placed at the end of the sentence.

All four sentences are grammatically fine, though simpler constructions would be better: "Ben Nevis is the highest mountain in Great Btritain." Please note, however, that there are many who consider themselves Scots who do not live in Scotland. The Scots diaspora is quite extensive.

All your sentences are correct, both logically and grammatically. If you want the ones that are closest in logical meaning to the given sentences, then that is 1 in both cases.