Emoji mappings in Shift JIS / CP932/943

[Christoph Päper]

I understand from 

- http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/readme.txt

that Windows codepage 932 (IBM CP943) is basically (a superset of) Shift-JIS (JIS X 0208 A1). There are at least 3 related mapping files:

- http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP932.TXT
- http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/bestfit932.txt
- http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/JIS/SHIFTJIS.TXT

I don’t know much about Shift-JIS, so this question may sound stupid: 
Could and should custom vendor extensions like the ones documented in

- http://unicode.org/Public/UCD/latest/ucd/EmojiSources.txt

be included in these mappings?

Related English Wikipedia articles:

- https://en.wikipedia.org/wiki/JIS_X_0208
- https://en.wikipedia.org/wiki/Shift_JIS
- https://en.wikipedia.org/wiki/Code_page_932
- https://en.wikipedia.org/wiki/Code_page_943

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Furthermore, are the files in /Public/MAPPINGS/ supposed to be maintained at all as characters get added to subsequent releases of Unicode? For instance, I think that

- http://www.unicode.org/Public/MAPPINGS/VENDORS/MISC/SGML.TXT

(dated 25 July 1997, last modified 8 April 2002) includes several `????` that could be specified nowadays, e.g.:

-     epsiv	ISOgrk3	0x????	# variant epsilon
+     epsiv	ISOgrk3	0x03F5	# GREEK LUNATE EPSILON SYMBOL