Yes, it's from the Chinese transliteration 荷蘭 (*Holan), based on a non-Pekingese pronunciation.
I think it's because "going to" is more like "sẽ", implying "at some point in the future", whereas "sắp" is more immediate which in English would be expressed with "about to". I could be wrong though...
I agree. That sounds logical and correct. The tips say "about to happen" which has a tone of immediacy to it.