An interesting example of exactly what I think we’re talking about, and sort of what I’m trying to talk about, is Frankie’s track on WFO1, Disk 2. ‘The Cat That Ate The Candle/Over The Water To Bessie’ are full of letter-perfect rolls and flips and turns and triplets, but they don’t really call attention to themselves as such – they serve only enhance the tune and the phrasing, never getting in the way of the pulse or the melody. In each case, I think you can hear the man doing exactly what’s right for the tune – that’s the case I was trying to make, anyway.
FWIW, his approach to those two tunes is quite different from his approach to ‘New Ships A Sailing’ (wonderful drive and lift aside, of course).
HOWEVER, a couple of considerations/questions … 1) solo playing vs. ensemble playing and how different they are by necessity; and 2) what about his own progress as a flute player? Did he get more ornamented as he played longer? Or, did he start simply, get more ornamented, then strip things back down?
Or was he indeed a player of fabulous taste as well as great ability (as I aver)?
I wouldn’t be surprised with him mirroring Mairead’s fiddling style – fiddles are it in Donegal as I understand. I can’t think of any Donegal flute players off the top of my head …
Plus, when the main person you play with has a certain style, how can you not be influenced by it? From personal experience … in my first flute lesson John told me I needed to learn to play more like a flute player and less like a fiddle player (my fella is a fiddler).
(Let me tell you, THAT’S been a journey.)
As for any other border/Northern players … Marcas O Murchu is from Belfast, Turlach Boylan is from around Derry, and then of course there are the border guys like my beloved John McKenna from Leitrim.
Sorry for the dog’s breakfast of thoughts – it’s all your fault, Lesl! 
xoxoxo,
cat.