In my experience, Chinese versions of foreign words, including foreign names, usually don't approach the sound of the original as closely as Chinese phonology allows. That is, they aren't really meant as "phonetic transliterations"; there are other options available purely within Chinese that would approximate the original sound more closely.[1]
Instead, the goal seems to be that you're in the right ballpark on the sound, and then you tweak the name for other factors such as character semantics while staying somewhere in the ballpark.
And of course, once a name is conventionalized, you'd want to use that rather than innovating a new version.
[1] Of course it's possible in general that while my foreign ears think a different Chinese syllable would better match the foreign one, the Chinese disagree and really believe they are using the closest available match. There are plenty of ready examples, such as Coca-Cola, where this is obviously not the case.
There is no one central authority in regard to Chinese names. Reporters in China, Hong Kong, or Taiwan — each of these regions is its own trademark jurisdiction — often have their own ideas. This results in multiple Chinese names for the same person, each with its own meanings and connotations that often are not the best.
And likewise for candidate names -- IIRC lots of people moved to BC from HK, but perhaps a minority by now?
Yes, it is the norm for older loanwords. Compare Mandarin jia-na-da [Canada] from Cantonese ga-la-da, or Mandarin mo-xi-ge [Mexico] from Cantonese mak-sai-go.
EDIT: it's worth observing that the Chinese themselves are generally not aware that the older loanwords came through Cantonese.
It feels safe to say the second syllable beginning with N in Mandarin was just good luck though. I might have swapped out the N for L anyway if I had known the Jyutping.
An example of a distinction that would have come through fine English -> Mandarin being lost by apparent transmission through Cantonese exists in Los Angeles, 洛杉矶. The Mandarin is luo-shan-ji, which annoys me every time I need to understand or produce the name. Mandarin has no problem distinguishing s from sh.
[1] https://en.wikipedia.org/wiki/EFEO_Chinese_transcription
Read your own link:
> The transcription of the EFEO did not borrow its phonetics from the national official Standard Mandarin. Rather, it was synthesized independently to be a mean of Chinese dialects, and shows a state of sounds a little older in form
In particular, for the Beijing case, South Mandarin is involved: https://en.wikipedia.org/wiki/Chinese_postal_romanization#Ma....