So?
The surname
Delaney IS from
Norman origin. The use or not to Anglicize a legit Irish surname doesn't change the etymology of the surname.
A lot of information about Irish history, but nothing about a phylological explanation to justify the Celtic linguistic origin of the form
Delaney (basically its linguistic evolution from Dubhslaine).
Your information and links only show that:
1) Dubhslaine is a historical Irish surname and name
2) and that it had been matched with the
Norman surname
Delaney to Anglicize it (as a lot of other Irish names and surnames which had been matched with non-related English names and surnames).
Lumia
http://onomastica.mailcatala.com