Ancient Greek apostrophe marking elision

[James Tauber via Unicode]

There seems some debate amongst digital classicists in whether to use
U+2019 or U+02BC to represent the apostrophe in Ancient Greek when marking
elision. (e.g. δ’ for δέ preceding a word starting with a vowel).

It seems to me that U+2019 is the technically correct choice per the
Unicode Standard but it is not without at least one problem: default word
breaking rules.

I'm trying to provide guidelines for digital classicists in this regard.

Is it correct to say the following:

1) U+2019 is the correct character to use for the apostrophe in Ancient
Greek when marking elision.
2) U+02BC is a misuse of a modifier for this purpose
3) However, use of U+2019 (unlike U+02BC) means the default Word Boundary
Rules in UAX#29 will (incorrectly) exclude the apostrophe from the word
token
4) And use of U+02BC (unlike U+2019) means Glyph Cluster Boundary Rules in
UAX#29 will (incorrectly) include the apostrophe as part of a glyph cluster
with the previous letter
5) The correct solution is to tailor the Word Boundary Rules in the case of
Ancient Greek to treat U+2019 as not breaking a word (which shouldn't have
the same ambiguity problems with the single quotation mark as in English as
it should not be used as a quotation mark in Ancient Greek)

Many thanks in advance.

James
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